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art0, ^timcts> anb ^Literature, 

ABRAHAM REES, D.D. F.R.S. F.L.S. S.Amer.Soc. 





Printed for LONGMAN, HURST, REES, ORME, & BROWN, Paternoster-Row, 



[( 001211965 ' S 







WATER. Tliis important fluid was believed by the an- 
cients to be one of the four elements out of which they 
imagined every other fubftance is compofed. This opinion 
maintained its ground for a very long period. At length, 
however, it began to be fufpefted, from the experiments of 
Van Helmont, Boyle, and others. Van Helmont (hewed 
that plants would grow for a very long time in pure water, 
whence it was concluded that water was capable of being 
' changed into all the fubftances found in vegetables. Mr. 
Boyle fuppofed, that by long digeftion and boihng in glafs- 
vefTels, he had converted water partly into an earth. Mar- 
graafF, who repeated his experiment, drew the fame conclu- 
fion ; but the opinion was never very generally admitted, 
and at length was proved to be erroneous, the earth being 
fliewn to be derived from the glafs-veflels employed in the 

The combuftible nature of hydrogen gas was obferved 
about the beginning of the 1 8th century, and the celebrated 
Scheele, many years afterwards, was the firft who attempted 
to difcover what was produced by this combuftion. In 
this, however, he did not fucceed ; nor were Macquer, 
Bucquet, Lavoificr, Dr. Prieftley, and others, who fub- 
fequently repeated the experiment with fimilar views, 
more fortunate. The diftingui(hed honour of difcovering 
the compofition of water was referved for Mr. Cavendifli, 
who, in 1 78 1, proved beyond a doubt that the combuftion 
of hydrogen and oxygen produced this fluid, and nothing 
elfe. Water, therefore, fmce the period jufl; mentioned, has 
been univerfally admitted to be compofed of thefe two 
gafeous principles. 

Water is found in abundance in every part of the globe, 
and is abfolutely neceffary for the exiftence of organized 
beings. When quite pure, as obtained by diftillation, it is 


pcrfeaiy traiifparent and colourlefs, and free from tafte 
and fmell. 

A cubic foot of diftilled water, according to the bed 
experiments, weighs, at a temperature of 40°, 437102.4946 
grains troy. Hence, a cubic inch of water at the fame 
temperature weighs 252.952 grains; and at the tem- 
perature of 60°, 252.72 grains. The fpecific gravity of 
water is always fuppofed to be, and it is made the 
meafure of the fpecific gravity of every other body. { See 
Specific Gravity, and Hydrostatics.) Water, at a tem- 
perature of 32", becomes fohd, and affumes the form of ice. 
In this flate it poffefles confiderable hardnefs and elafticity, 
and its fpecific gravity is diminilhed to .94. See Freezing, 
and Ice. 

When water is raifed to the temperature of 2 j 2° it boih, 
and is gradually converted into fteam, which is an invifible 
and highly elaftic fluid like air. The fpecific gravity of 
fteam, according to the moft recent obfervations, is .625, 
that of air being reckoned See Boiling, Ebux- 
LiTioN, and Steam. 

Water is capable of undergoing a flight degree of com- 
preflion. See Compression. 

Water undergoes no alteration by expofure to heat or 
light. Thus it may be made to ,pafs through a red-hot 
tube without fuffering any change. 

On expofure to the atmofphere, it abforbs a portion of 
air, the greater part of which is capable of being agahi 
driven off by boiling. To expel the whole, however, it w 
ftated to be neceilary to continue the operation at leaft two 
hours in a flaflt, with its mouth inverted over mercury. 
To this fmall proportion of air which it holds in folution, 
water chiefly owe* its agreeable flavour, boiled water being 
infipid. See Absorption, and Gas. 

B Hydrogen 

Primed by A. Strahaii, 
Nev»-Street-St|uare, Lojido 


Hydrogen gas, c%-cn at a red heat, has no aftion upon to the neighbourhood of Tolcanoes, but generally their 
water. Charcoal, when cold, does not decompofe it. But caufe is very obfcure, as \ve can hardly form any idea of 
when red-hot charcoal is brought in contaft with water, agents operating for fuch a length of time, and fo uniformly, 
carbonic acid and carburelted hydrogen are formed in as thofe of neccffity mull do which give origin to the phe- 
abundancc Sulphur and phofphonis do not appear to be nomcna in qucllion : all we can infer is, that although local, 
capable of decompofing water, even when alTifted by heat ; they are deep-fcated and permanent. 

but potaffmm and fodium, and doubtlefs alfo the metallic 2. Atmofphinc Air : A%ote.—h\\ natural waters of a 
bafes of the alkaline earths, decompofe it rapidly. Of the mean temperature hold a portion of common air in folution. 
other metals, iron, zinc, antimony, and tin, decompofe it, The quantity, however, has been ftated by Bergman not to 
when aflifted by heat. Silver, gold, copper, and platina, exceed Vuth of the bulk of the water ; and even this can 
produce no efFeA upon it. °"'y ''^ retained at a mean temperature, and under the ordi- 

Water difTolves the alkalies and alkaline earths. The acids nary preffurc of the atmofphere, for the greater part of it 
alfo, and many faline compounds, arc fohible in this fluid ; cfcapes under the air-pump, or on fubmitting the water for 
but 'it is incapable of diffolving the earths properly fo called, a Ihort time to a temperature of 212° or 32°. It is the 
Water combines with bodies in two different ways. It oxygen contained m this fmall portion of atmofpheric air, 
either difTolves them, in which cafe the proportion of water retained by water, that fupports the refpiration of fifties, and 
is unlimited, or it combines with them, and forms folid other aquatic animals, which fpeedily die from fufFocation in 
compounds, 'termed hydrates, into the compofition of which water deprived of air. It is this air alfo, as before obferved, 
the water enters in a definite proportion. The metallic which renders water fapid and grateful to tl e palate ; for 
hydrates, in geiiTal, are remarkable for the brilliancy of by boiling or diilillation, this fluid is rendered iiifipid and 
their colours. They are more foluble in acids than the difagreeable, " and has long been in difreputc," fays Dr. 
oxyds, and in lome iaftances affeft the organs of tafl;e even Saunders, " for lying heavy on the ftomach, and even pro- 
more perceptibly than the metallic falts. This fubjeft has ducing fcrofulous tumours and obftruftions." The pre- 
beea particularly invelligatcd by M. Proud. See Hydrate, fence of atmofpheric air in water is eafily accounted for. 
According to the lateft and moil perfeft experiments, from tlie aftinity which fubfiils between the two fubllances, 
water is compofed of two volumes of hydrogen gas, and and which is fuch, that they foon become mutually impreg- 
one volume of oxygen gas. Hence, its combining weight nated by being expofed to each other — Azotic gas has 
or atom will be 1.125, oxygen being reckoned 1 ; or, if been found to exifl iii fmall quantity in fome waters, and in 
we confider the fpecific gravity of hydrogen gas to be thefe inftanccs it has been obferved to be extricated from 

'^ -'" - 1 -/•-_:.._ :.rir;_ .._: :.u .u- ^-^^ex. As far as is at 

I medicinal or even fenfible 

water is attended by the extrication of much light and heat. 3. Carhonic And. — This gas is likcwife dated by Berg- 
See CoMBt'STiON and Deton.\tion. man to exift in greater or lefs quantity in all natural fpring- 
Watkrs Natural. " Water," fays Dr. Saunders, " is waters. The limits in which it occurs is faid to lie between 
found throughout the earth in every degree of purity, ex- about -rjir, and an equal bulk of the water. In mineral 
ccpt the higheft, for fuch is never procured, except by arti- waters it is a moft important ingredient, not only from its 
ficial diftillation, as all natural waters are conftantly coming operation upon the animal economy, but from its being the 
into coDtaft with fome fubftance which they can cither dil- folvent of various otlier aftive ingredients. When waters 
folre or hold fufpended." Waters to which the epithet contain this principle in excefs, they affume a bright and 
mtural is applied, in many inftances differ from other natural fparkling appearance to the eye, have an agreeable pungent 
waters in the degree only in which they are impregnated with acidulous taile, and fometimes exert a kind of intoxicating 
fimilar foreign fubftances : in other inftances, they differ in power when largely drunk. Fifties are unable to exift in 
the nature of the impregnating ingredient ; but for the them, and fpeedily die from fuffocation. On expofurc to 
moft part they differ in both thefe circumftances. In pre- the air, however, thefe properties in a Ihort time become 
fenting our readers with an account of natural waters in fenfibly diminiftied, and at length alnioll totally difappear, 
general, we fhall commence with an enumeration and ftiort owing to the feparation of the gas — an operation which 
account of the different foreign ingredients ufually met may Hill more fpeedily be effetled by boiling. The pre- 
with in waters, and influencing their operation o;i the animal fence of this gas in water is eafily explained, from its natural 
economy. affinity to that fluid. In almoft every iiiftaiice it is extri- 

1. Caloric. The temperature of natural fpring-waters is cated from the fpring in union with the water; but the 

the fame, in general, as the mean annual temperature of the fource from whence it is derived is, in general, obfcure and 

pwticular place in which they occur. It is evident, there- inexplicable. 

fpre, that this temperature muft vary with the latitude. 4. Hydrogen and its Compounds, carburelted, fulphuretted, 

(See the articles Climate, Temperature, &c.) Waters and phofphurctted Hydrogen — Hydrogen gas is barely folu- 

rarely occur of a temperature much lower than the mean ble in water, and probably, therefore, never exifts alone 

annual temperature of the latitude in which they are found ; in that fluid. The fame is true of carburetted hydrogen. 

but inftanccs arc met with in every part of the globe in Both thefe gafes, however, are often extricated from waters, 

which they occur of a higher temperature. This degree efpecially when ftagnant, and containing organic fubftances 

of increafed temperature is very different in different in- in a ftate of putrelaAion. Sulphuretted hydrogen is a fre- 

ftances. Commonly it is not very ftriking, while in other quent ingredient in mineral waters, and gives them fo cha- 

cafes it is very remarkable : thus, the waters of Carlft)ad, in rafleriftic a feature, that thoy are inftantly recognized. 

Bohemia, have the extraordinary temperature of 165". In Waters holding this gas in folution have an offciifive fmcU, 

this country, the hotttft fprings are thofe of Bath and like that of rotten eggs, or a foul gun-barrel, and which is 

Buxton, the higheft temperatures of which are dated to be more or lefs ftrong, according to the degree in which they 

116° and 82" refpedivcly. In fome inftances, thefe devia- are impregnated. Such waters alfo have a tafte fomewhat 

tioni from the natural temperature arc obvjoufly rcferriblc fwcetifh, and they generally appear turbid. Water, at a 



mean temperature, is ftated to abforb from }ds to ^ths of 
its bulk of this gas, and by long agitation more than its 
bulk. At a temperature of 80° or gd^, however, this fluid 
can with difficulty be made to diilbtve any of it. Sul- 
phuretted waters, therefore, on expofure to heat, or even 
to the open air without heat, foon lofe their charafteriftic 
properties, and become turbid, the hydrogen being difli- 
pated, and the fulphur depofited. The fource of this gas, 
in general, is not obfcure, it being formed in great abun- 
dance during the decompofition of pyrites, and other mine- 
rals containing fulphur. Phofphuretted hydrogen is faid 
to be occafionally extricated from marfties and ftagnant 
pools, but it is not known to conftitute an ingredient in 
mineral waters. 

5. The Alkalies and their Salts. — The fixed alkalies feldom, 
if ever, occur in natural waters in a free ftate. Even the 
number of their falts is fo limited, that Dr. Saunders 
thinks it neceflary to enumerate only two, namely, the ful- 
phate and muriate of foda. The firft of them is a very 
common ingredient in mineral waters, but rarely occurs 
alone in any quantity, fo that it can hardly be faid ever to 
give a peculiar charafter to a water. Muriate of foda is 
10 extenfively and abundantly difFufed through nature, 
that we rarely meet with a natural water which does not 
contain more or lefs of it. Sea-water, and many natural 
waters or brines, owe their peculiar charafters to this fait, 
which has been known from the earlieft times, and feems to 
be almoil a neceflary ingredient in our food. The muriate 
of foda, however, never occurs alone in natural waters, but 
is commonly accompanied by fome of the earthy falts, 
efpecially the fulphate of lime. Chemilts have been puz- 
zled to account for the origin of the vaft quantity of this 
fait which is met with in the fea and elfewhere ; but a 
little refleftion will fhew, that the exiftence of this fub- 
ftance is not more difficult to be accounted for than that 
of any other ingredient of our globe. From its property 
of being foluble in water, it is, perhaps, more generally dif- 
fufed than any other principle ; but it is doubtful if it 
aftually exilts in greater abundance than filex, and many 
other folid fubftances, and which, in a geological point of 
view, differ from it only in the mechanical circumfl;ance of 
their infolubility in water. The carbonate of foda is occa- 
fionally met with in waters. Its difl:ribution, however, is 
very partial, being ufually in very minute quantities, or in 
very large ones. When in fmall quantity, it is generally 
fuperfaturated with carbonic acid. The moft remarkable 
inftance of an excefs of this fait is in " the natron lakes 
of Upper Egypt. It is here often mixed with common 
fait, and they both are largely diflblved in the water, and 
form a cruft of feveral feet in thicknefs at the edge of the 
lake, owing to the copious evaporation of their water of 
folution eftefted by a tropical fun." Potafh, or its falts, 
very feldom occur in mineral waters. Carbonate of am- 
monia is occafionally found in fmall quantities in fome waters, 
arifing probably, as Dr. Saunders conjedlurcs, from decom- 
pofed animal or vegetable fubftances. 

6. The Earths and their Salts. — The earth moft fre- 
quently occurring in natural waters is lime, and fo gene- 
rally is this the cafe, that very few inftances are known in 
which this earth is not met with in fome ftate or other. 
The neutral carbonate of lime, or chali^, is one of the moft 
infoluble fubftances known ; but the fupercarbonate of 
lime is very foluble, and is a frequent ingredient in many 
fprings. " It is one fource of hardnefs in waters," fays 
Dr. Saunders, " but is eafily got rid of by boiling, which 
drives off' the excefs of carbonic acid, and thus caufes the 
ehalk to be precipitated ; hence the earthy cruft or furr on 

kettles in which hard water has been boiled for a number of 
times. Some natural waters contain an unufual quantity of 
this calcareous earth, which is rapidly depofited as foon 39 
they become expofed to the air, and thereby give an earthy 
hning to every tube through wliich they flow, and encruft 
with the fame material every fubftance that accident or 
defign may put in their way. Of this kind ai-e the various 
petrifying fprings that form pai-t of the natural curiofities 
of feveral mountainous diftrifts, and have been applied to 
ufe in a very ingenious manner at the baths of St. Philip, 
in Tufcany, and llill more extenfively at Gualecavelica, in 
Peru." — " The fulphate of lime (the gypfum or felenite of 
the older writers) is one of the commoneft of all the earthy 
falts that are found in natural waters, and generally ac- 
companies every faline fubftance, except where there is an 
excefs of alkali. It is almoft invariably found in con« 
junftion with the carbonate of lime ; and hence the calca- 
reous depofitions, petrifaftions, and the hke, frequently con- 
tain a fmall admixture of felenite." This fait imparts very 
little tafte to water, but gives it " that rough and harfh 
feel to the fingers and tongue, which charaAerize the 
infipid hard waters." The muriate of lime commoply ac- 
companies the other falts of lime, but efpecially the muriate 
of foda. When in excefs in any water, it imparts to it a 
bitter and difagreeable tafte, and adlive medicinal properties. 
The great bitternefs of " the waters of the Dead fea is 
owing to the muriates of lime and magnefia, and not to 
bitumen, as was erroneoufly fuppofed." The carbonate of 
magnefia is infoluble in water ; the fuparcarbonate of 
magnefia, when it occurs in waters, is always accompanied 
by the fupercarbonate •f lime, both the earths being held 
in folution by an excefs of carbonic acid. The fuper- 
carbonate of magnefia, however, is more foluble than the 
fupercarbonate of lime, and is not, therefore, fo eafily 
fcparated by boiling. The fulphate of magnefia, or jE^« 
fait, as it was formerly denominated, is the moft important 
of the falts of this earth. It almoft always accompanies the 
fulphate of foda ; and to thefe two falts moft of the natural 
purging waters owe their cathartic properties. It is like- 
wife frequently combined with the fulphate of lime, and 
alfo with iron. The fulphate of magnefia imparts to the 
waters containing it in any confiderable quantity a ftrongly 
bitter and faline tafte. It was firft difcovered in a fpring 
at Epfom, whence its name ; but is ufually prepared at 
prefent from the refufe fait of fea-water, after the common 
fait has been feparated. The muriate of magnefia, as before- 
mentioned, commonly accompanies the muriates of foda and 
lime ; hence it is found in various brine-fprings, and forms 
a confiderable part of the faline contents of fea-water, to 
which fluids, efpecially when concentrated by evaporation, 
it imparts a ftrong bitter tafte. Salts of alumina are not 
of very frequent occurrence in waters. The moft common 
is the fuperfulphate of alumina, or common alum, which is 
ufually aflbciated with the fulphate of iron. The fource 
of this fait is for the moft part alum-flate, the fulphur 
contained in which becomes acidified on expofure to 
the air, and forms fulphuric acid, which, uniting v.-ith the 
alumina, produces the fait in queftion. The' prefence of 
the fulphate of iron is eafily accounted for upon iimilar 
principles, fince more or lefs of iron pyrites almoft in- 
variably accompanies alum-flate. Silex, in a ftate of mi- 
nute divifion, is fometimes found fufpended in fmall 
quantity in running waters, but is foon depofited on their 
remaining at reft. This earth, however, occafionally occurs 
in a ftate of folution in hot and tepid fprings, efpecially in 
the neighbourhood of volcanoes. The menftruum appears 
to be ufually a little free or carbonated alkali, the lolvent 
B 2 powers 


powers of which are doubtlefs much increafed by heat, or 
by fomc unknown caufe. 

7. Metals and their Salts — The metal mod ufually met 
with in natural waters is iron; newr, however, in its me- 
tallic ftate, but in a ftate of oxyd combined with an acid. 
The carbonate of iron is a frequent ingredient of natural 
waters, the bafe of whicli is the black or protoxyd of the 
metal, for the red oxyd docs not feem capable of combining 
with carbonic acid, or at lead of forming with it a foluble 
compound. This is, doubtlefs, a wife provifion of nature ; 
for, as Dr. Saunders julUy obferves, if tlic contrary were 
the cafe, almolt every natural water would be a chalybeate. 
The carbonate of iron, like all tlie other falts of this metal, 
imparts to waters containing it a peculiar inky tafte, 
" which," fays Dr. Saunders, " is very perceptible, even 
when the proportion of iron is fo fmall as hardly to be 
cftiraable by any chemical procefs." Waters containing 
the carbonate of iron depofit this metal readily on expofure 
to the air, partly from the efcape of the carbonic acid, and 
partly from the further oxydation of the metal. The ful- 
phate of iron or green vitriol is met with occafionally in 
waters in confiderable quantity. This fait, as before ob- 
ferved, generally occurs in union with the fulphate of alu- 
mina, or alum, and is the natural produftion of the decom- 
pofition of iron pyrites. Waters containing this fait in any 
quantity, poflefs the properties of chalybcates in a higli 
degree, and are peculiarly ftyptic. The muriate of iron is 
occafionally met with in natural waters ; but its exiftence 
in any confiderable quantity is a rare occurrence. Copper, 
or rather its falts, and efpecially the fulphate of copper, is 
occafionally met with in natural waters. This generally, 
however, occurs in the neighbourhood of copper-mines ; 
and the fulphat! of copper, as Dr. Saunders obferves, is 
probably formed, like the fulphate of iron, by the decom- 
pofition of copper pyrites. Waters containing this metal 
are highly poifonous, and are never ufed internally. Man- 
ganefe is occafionally found in fmall quantity in natural 
waters. It appears, in general, to be aitociated with iron ; 
but the ftate in which it exiits is not accurately known. 
As far as prefent obfervation goes, it imparts no fenfible 
or other properties to the waters containing it. Lead, per- 
naps, never naturally occurs in waters ; but fome waters 
..ave the property of difiblving, or holding in fufpenfion, a 
minute portion of this pernicious metal, when expofed to it 
in the metallic ftate. Pure foft waters are faid to poflefs 
this property in the moft ttriking degree. 

8. Mineral Acids. — Both the muriatic and fulphuric acids 
are occafionally met with in mineral waters in a free ftate. 
Such fprings ufually occur in volcanic countries. 

9. Bitumen Bitumen is faid by many of the older 

writers to be a frequent ingredient in mineral waters. Tliis 
ftatement, however, has been generally found erroneous by 
modern chemifts, who have in moft cafes demonftrated the 
fuppofed bituminous principles of their predeceflbrs to be 
fubftances of a very different nature. There are fome 
fprings, however, which yield a real bitumen ; but this, 
from its infolubility in water, is never diffolved in that fluid, 
except in a few rare inftances, through the medium of an 

Such is a fliort account of the principal mineral fub- 
ftances which are met with in natural waters when they 
itlue from the earth. " When," fays Dr. Saunders, " they 
flow within a channel over the furface of the ground, they 
often become much changed in their chemical compofition, 
loiing fome of their contents by evaporation, others by flow 
drpofition, or by being decompofed through the influence 
of light and air. At the fame time they often acquire new 

contents, which are furniflied by the foil over which liiey 
flow. Tlius the ftreams which pafs over a country covered 
with vegetable matter, or which water large towns, will 
contain a fenfible quantity of mixed alluvial contents, or a 
heterogeneous compound of animal and vegetable extrad of 

Different authors have chofen different principles ot 
arrangement in treating of natural waters. An arrange- 
ment purely chemical, or purely medicinal, cannot be 
effefled in the preient ftate of our knowledge ; we ftiall 
not therefore attempt either, but ftiall confider them under 
the following heads : 

1. Potable waters. 

2. Saline waters. 

3. Chalybeate waters, fimple and compound. 

4. Acidulous waters, fimple and compound. 

5. Sulphureous waters, fimple and compound. 

6. Thermal waters, fimple and compound. 

This arrangement of natural waters, according to their 
fenfible properties, coincides likewife, as well perhaps as 
the prefent ftate of the fubjeft will admit, with their chemi- 
cal and medicinal properties. It may, however, be objefted 
to the diviGons_/;m//c and compound, that neither of them is 
accurately correft, and this muft be admitted in a ftri£lly 
chemical point of view ; but taken in the enlarged and gc- 
nenU fcnfe here underftood, there feems to be no fcrious ob- 
jrttion to this mode of divifion. 

I. Potable Waters. — Under this divifion we wiftl to in- 
clude every variety of this fluid ordinarily ufed by mankind 
and other animals for fatisfying their thirft. Thefe may be 
comprehended under the heads of, a, pure or diftilled water ; 
b, atmofpheric water; c, fpring-water ; d, running water ; 
and e, ftagnant water. 

a. The choniical properties of pure water have been al- 
ready dcfcribed at the head of this article. As before ob- 
ferved, it never occurs in nature, and was therefore pro- 
bably never intended as an article of drink for mankind ; cer- 
tainly, at leaft, not as one abfolutely neceflary for their ex- 
iftence, or even healthy condition. 

b. Under atmofpheric waters are included rain-water, fnow- 
water, dew, S;c. 

Rain-water, collefled at a diftance from large towns, or 
any other objeft capable of impregnating the atmofphere 
with noxious materials, approaches more nearly to a ftate of 
purity than perhaps anv other natural water. Even collect- 
ed under thefe circumftanees, however, it invariably yields 
traces of the muriatic acid, and, according to Margraaff, 
of the nitric alfo. Rain-water of courfe differs according 
to tlie ftate of the atmofphere through which it paffes. 
" The heterogeneous atmofphere of a fmoky town," fays 
Dr. Saunders, " will communicate fome impregnation to rain 
as it paffes through ; and this, though it may not be at once 
perceptible on chemical examination, will yet render it liable 
to fpontanecus cliange : and hence rain-water, if long kept, 
efpecially in hot climates, acquires a ftrong fmell, becomes 
full of animalculx, and in fome degree putrid." Rain-water 
in general, in warm climates, is much more impure and lia- 
ble to become offenfive than in cold and temperate ones. 
Rain alfo that falls in the fpring and fummer, or after a 
long-continued drought, or very hot weather, is faid to be 
more impure than that which falls at other feafons of the 
year, or after a long-continued moift feafon ; circumftanees, 
doubtlefs, owing to the exiftence of a greater proportion of 
animal and vegetable principles in the atmofphere in fuch 
climates and feafons. Thefe foreign fubftances have forac- 
timcs been fo abundant and peculiar in tlicir appearance, as 


to have given origin to many marvelloub Hones, fuch as the 
raining ot blood, &c. (See the article Rajn.) The fpe- 
cific gravity of rain-water hardly differs from that of dif- 
tilled water ; and from the minute portions of the foreign 
ingredients which it generally contains, it is very foft, and 
admirably adapted for many culinary purpofes, and various 
procefles in different manufattures and the arts. 

SHonv-tvuter equals, if not furpafles, rain-water in purity, 
when collected under the fame circumftances, it being 
for obvious rcafons more free from animal and vegetable 
impregnations ; thus Dr. Rutty found it perfeftly fweet 
after keeping it in a clofe veflel for eighteen months. Snow- 
water, like rain-water, even in its pureft ftate, yields traces 
of muriatic acid, and perhaps alfo of the nitric. 

Ha\l--waUr may be compared to fnow-water, which it 
clofely refembles : indeed 

Ice-water in general is very pure, as the air and faline fub- 
ftances are feparated by freezing. Common ice-water, how- 
ever, is lefs pure than rain and fnow water, as the foreign 
fubftances, though perhaps feparated by freezing, ftill re- 
main incorporated with the ice, fo that it is impoflible to 
melt the ice without retaining at leaft a portion of thefe fo- 
reign matters. 

Dewy being depofited chiefly from the lower parts of the 
atmofphere, is commonly much more impure than rain or 
fnow water. According to Dr. Rutty's obfervations, it 
foon becomes fcetid and offenfive. It yields alfo more fenfi- 
ble traces of the prcfence of muriatic acid than rain-water. 
This fluid, however, collected at different places and 
times, differs exceedingly in its properties, as might be na- 
turally expefted. 

c. Spniig-water includes mell-watcT, and all others that 
ariie from feme depth below the furface of the earth, and 
which are ufed at the foimtaiii-head, or at leaft before they 
have run any confiderable diflance expofed to the air. Al- 
though all fpring-waters are originally of atmofpheric origin, 
yet they differ from one another according to the nature of 
the foil or rock from which they iffue ; for though the in- 
gredients ufually exifting in them are in fuch minute quanti- 
ties as to impart to them no ftriking medicinal or fenfible pro- 
perties, and do not render them unfit for common purpofes, 
yet they modify their nature very confiderably. Hence the 
water of fome fprings is faid to be htiril, others frft, fome 
/•wect, others Iracli/h, &c. according to the degree and nature 
of the impregnating ingredients. Common fprings pafs mfen- 
fibly into mineral or medicinal fprings, as their foreign con- 
tents become larger or more unufual ; or in fome iriflances 
they derive medicinal celebrity from the abfence of thofe in- 
gredients ufually occurring in fpring-water ; as, for example, 
is the cafe with the Malvern and other fprings. Almoft all 
fpring-waters pofTefs the property termed hardnefs in a greater 
or lefs degree. This hardnefs, as we formerly mentioned, 
depends chiefly upon the fulphate and carbonate of lime 
which they hold in folution. The quantity of thefe earthy 
falts varies very confiderably in different inilances ; but Dr. 
Saunders obferves, that when they exift in the proportion of 
five grains in the pint, fuch water will be hard, and from 
its property of decompofing foap will be unfit for wafhing, 
and many other purpofes of houfehold ufe or manufaftures. 
The water of deep wells, according to Dr. S., is always, 
ceteris parilus, much harder than that of fprings which over- 
flow their channel ; but there are many exceptions to this rule. 
The fofinejs of fpring-waters depends on their containing 
fmaller proportions of the earthy falts above-mentioned. 
Spring-waters are faid to be brackifh, when they contain a 
fmall proportion of the muriates of foda, magneiia, or lime, 
26 is frequently the cafe in the neighbourhood of the fea. 

Siveelnefs is generally underitood as oppofed to brachjhnefs ox 
Jtitor when apphed to fpring-waters. The fpecific gravity 
of fpring-waters in general is greater than that of dillilled 
or any other potable water. See Spring. 

d. Running waters include /v'l^fr-waters, and every other 
ipecies of water eXpofed to the air, and moving in an open 
channel. On this part of our fubjeft we cannot do better 
than quote from Dr. Saunders. " River-water," fays Dr. 
S., " in general is much fofter, and more free from earthy 
falts than fpring-waters, but contains lefs air of any kind ; 
for by the agitation of a long current, and, in mofl cafes, a 
great increafe of temperature, it lofes common air and car- 
bonic acid, and with this lafl much of the hme which it 
held in folution. The fpecific gravity thereby becomes lefs, 
the tafte not fo harfh, but kfs frefh and agreeable, and out 
of a hard fpring is often made a ftream of fuflicient pu- 
rity for mofl of the purpofes where a foft water is required. 
Some ftreams, however, that arife from a clean iilecious 
rock, and flow in a fandy or flony bed, arc from the outfet 
remarkably pure, fuch as the mountain lakes and rivulets 
in the rocky diflrifts of Wales, the fource of the beautiful 
waters of the Dee, and numberlefs other rivers that flow 
through the hollow of every valley. Switzerland has long 
been celebrated for the purity and excellence of its waters, 
which pour in copious ftreams from the mountains, and give 
rife to fome of the fineft rivers in Europe." — " Some rivers, 
however, tliat do not take their rife from a rocky foil, and 
are indeed at full confiderably charged with foreign mat- 
ter, during a long courfe, even over a richly cultivated plain, 
become remarkably pure as to fahne contents, but often 
fouled with mud and vegetable or animal exuvix, which are 
rather fufpcndcd than held in true folution. Such is that of 
the Thames, which, taken up at London at low water, is 
very foft and good water, and after reft and filtration it 
holds but a very fmall portion of any thing that could prove 
noxious, or impede any manufadture. It is alfo excellently 
fitted for fea-ftore, but it here undergoes a rema; kable fpon- 
taneous change. No water carried to fea becomes putrid 
fooner than that of the Thames. When a cafl< is opened, 
after being kept a month or two, a quantity of inflammable 
air (carburetted or fulphuretted hydrogen) efcapes, and the 
water is fo black and offenfive as fcarcely to be borne. 
Upon racking it off, however, into large earthen veflfels, 
and expoiing it to the air, it gradually depofits a quantity of 
black flimy mud, becomes clear as cryflal, and remarkably 
fweet and palatable. The Seine has a high reputation in 
France, and appears, from the experiments of M. Parmentier, 
to be a river of great purity. It might be expected that a 
river which has paffed by a large town, and received all its 
impurities, and been ufed by numerous dyers, tanners, hat- 
ters, and the like, that crowd to its banks for the conve- 
nience of plenty of water, fhould acquire thereby fuch a 
foulnefs as to be very perceptible to chemical examination 
for a confiderable diftance below the town ; but it appears 
from the moft accurate examination, that where the ftream 
is at all confiderable, thefe kinds of impurity have but little 
influence in permanently altering the quality of the water, 
efpecially as they are for the moil part only fufpended, and 
not truly diffolved ; and therefore mere refl, and efpecially 
filtration, vsill reftore the water to its original purity. Pro- 
bably, therefore, the moft accurate chemift would find it 
difficult to diftinguifh water taken up at London from that 
procured at Hampton-court, after each had been purified by 
fimple filtration." The water of the Ebro alfo, notwith- 
ftandir.g this river pafTes through feveral large towns, is re- 
markable for its purity. In general, thofe rivers which iffue 
from lakes are moil pure and tranfparent, while thofe chiefly 



fuppUcd by fpringa and rain are die revcrfe. The water of 
fome rivers is remarkable for its colour : thus that of the 
Tinto, in Spain, at its fource is of a fine topaz, a circum- 
ftance from whicli the river takes its name. Others are of a 
yellowilh or greyith-white, and the water of all fuch rivers 
ufually holds a large proportion of fome fait of lime in folu- 
tion. In countries where bogs and marlhes abound, the 
rivers are often tinged of a browni(h colour. 

e. Slacfiant IValers. — Under this head are included the 
waters of lakes, pools, and rcfervoirs of every defcription, 
in which this fluid is expofed to the air in a (late of relt. 
Stagnant waters, in general, prefent greater impurities to the 
fenfes than any otiicrs, from their ufually containing a large 
proportion of animal and vegetable matters in a ftate of de- 
compofition. Their tafte in general is vapid, and delli- 
tute of that frefhnefs and agreeable coolncfs which diftiu- 
guifh fpring-water. Stagnant waters have various origins, 
but ufually they are a mixture of rain, fpring, and river 
water ; and hence, befides the animal and vegetable matters 
they contain, may be fuppofed to be impregnated with the 
various faline matters ufually met with in fuch waters. Many 
flagnant waters are faid to contain the nitrate of potalh ; 
others, and efpecially fome lakes, abound in the fulphate 
of raagnefia ; others m the carbonate of foda, as, for exam- 
' pie, the natron lakes of Egypt and Hungary, which are 
generally very (hallow. A lake in Thibet is impregnated 
with the borate of foda mixed with the muriate of foda, the 
waters of which feem to have a fubterranean origin. Some 
lakes alfo are found impregnated with fulphuretted hydrogen 
gas. Stagnant waters are feldom perfeftly colourlefs and 
tranfparent. Lakes, when deep, are ufually of a blueifh 
tinge, mixed with green ; and when the neighbouring hills 
are covered with peat, &c. their water is always of a muddy- 
brownifh tinge, as, for example, is the cafe with mod of 
the lakes in Scotland. 

I. Ufes of Potable Waters. — If we were to be direftedby 
the evidences of the fenfes alone, fpr'mg-viaX.nri would un- 
doubtedly be pronounced to be the mod wholefome, for they 
are univerfally admitted to be the moll agreeable. All 
other waters have more or lefs of a flat infipid tafte. This 
is efpecially the cafe with diftilled and rain water ; the firft of 
which is quite pure, and the fecond nearly fo. Diftilled 
water, therefore, is feldom employed for drinking ; and the 
difficulty of procuring it in large quantities almoft precludes 
its ufe to any extent in the preparation of food, or in manu- 
faftures. Much, however, has been lately faid of its me- 
dicinal powers by Dr. Lambe, who has recommended it in 
cancerous and other affeftions ; and, as Dr. Saunders juftly 
obferves, water, wlien not already loaded with foreign mat- 
ters, may become a folvent for concretions in the urinary paf- 
fages ; and as much good has been obtained from the ufe of 
very pure natural fprings, acourfe of diftilled water may be 
confidered as a fair fubjeft of experiment. Di/lilled water 
is an elTential ingredient in the compofition of many medi- 
eincs, and often abfolutuly ncceliary in the profecution of 
all nicer chemical procefTes in the liquid way. Snow and 
ice water form almoll the conftant drink of the inhabitants 
of cold climates during wiuter ; and the mades of ice which 
float on the polar fcas afforj an abundant fupply of fre(h 
water to tlie mariner. " Sno'w-v.aUT," fays Dr. Saunders, 
"httS long lain under the imputation of occafioning thofe 
ftrumous fwoUings in the neck which deform the inhabitants 
of many of the Alphic valk-ys ; but this opinion is not fup- 
porled by any well-authenticated indifputablc fadls, and is 
rendered ftill more improbable, if not entirely overturned, 
by the frpquency of llic difeafe in Sumatra, where ice and 
fnow are never feen, and its being quite unknown in Chili and 

Thibet, though the river* of thofe countries are chiefly (up- 
plied by the melting of the fnow with which the mountains 
are always covered." Dew, efpecially when coUeAed in the 
month of May, was formerly in great repute as a cofmetic, 
and for many other purpofcs ; but its ufe has been long en- 
tirely laid afide. Spriiig-wztcrs, as before obferved, from 
the air they contain, and from their grateful coolnefs, con- 
ftitute by far the moft agreeable of the potable waters, and 
are in more general ufe than any others. Their ufe, how- 
ever, is Hated fometimes to occafion in delicate ftomachs an 
uneafy fenfe of weight, followed by a degree of dyfpepfia. 
They have alfo been accufed, efpecially when of tbe de- 
fcription termed hard, of inducing calculous aSc£l.ions ; but 
this notion by moll modern writers is confidered as ill- 
founded. Spring-watCTS, in general, alfo, from their pro- 
perty of hardnefs, are, as before obferved, very ill adapted 
for many domeftic and other purpofes ; while, in particular 
inftances, this quality is of advantage. Hard ^r/n_f- waters, 
for example, are very ill adapted for the purpofes of the 
dyer or bleacher. " On the other hand," fays Dr. Saunders, 
" there are feveral faline fubftances which are very readily 
foluble in any kind of water, and here a hard water may be 
employed when the objeft is only to procure thefe particu- 
lar falts. For culinary purpofes, water is ufcd either to foften 
the texture of animal or vegetable matter, or to cxtraA 
from it, and prefent in a liquid form fome of its foluble parts. 
Soft pure water will fulfil botii thefe objedls better than hard 
water ; and at the fame time the colour of the fubllance etn- 
ployed will vary as well as its folution. Green vegetables 
and pulfe are rendered quite pale, as well as tender, by boil- 
ing in foft water ; whrreas in a hard water, the colour it more 
preferved, and the texture lefs altered, becaufe in the former 
cafe the colouring matter of the vegetable is readily extraft- 
ed by the menftruum, whilft in the latter more of it remains, 
and is likewife altered by the chemical aftion of the earthy 
or neutral falts." Dr. S. the» relates fome comparative 
experiments he made with hard and pure water upon 
tea ; from which he concludes that hard water is lefs pow- 
erful in foftening the texture of vegetable leaves than foft 
water, and that it is not able to exert its full effcdt in 
heightening their colour till alfifted by heat ; and alfo, tliat 
the galhc acid (or tannin) is equally wellextraded by hard 
as by foft water, when by raifing the temperature, the 
power of the former as a folvent is fully exorcifed. It may 
be therefore laid down as a geniJral rule \n domeftic economy, 
that when the objeft is to extraft the virtues of any fub- 
ftance, and to retain them in folution, foft waters (hould be 
ufed ; but that when the objeA is the revcrfe, or to prefervc 
as entire as poflible the article ufed as food, hard waters are 

Some fine fprings of very pure and foft water have been 
long celebrated for their medicinal properties ; as, for ex- 
ample, the Malvern fprings, in Worcefterfhirc, and St. 
JVinifrid's Well, at Holywell, in Flintfliire. Malvern 
water is ufcd both externally and internally. Externally 
apphed, it is ftatcd to be a moft ufeful application to deep- 
feated ulcerations of a fcrofulous nature, and to various 
cutaneous affeAions. Its internal ufe is often of advantage 
" in painful affeftions of the kidne)s and bladder, attended 
with the difcharge of bloody, purulent, or foetid urijie ; the 
heftic fever produced by fcrofulous ulcerations of the 
lungs, or very cxtenfive and irritating fores on the furface of 
the body ; and alfo fiftulas of long Sanding, that have been 
neglefted, and have become conftant and troublefomc fores." 
The internal ufe of this water fomelimes induces naufea at 
firft, and occafionally drowfincfs, vertigo, and head-ache, 
which foon go off, or may be readily removed by a mild 



purgative. This water occafionally purges, but mod com- 
monly the body becomes coftive under its ufe. " In all 
cafes, it increafes the flow of urine, and improves the gene- 
ral health of the patient ; fo that his appetite and fpirits 
alnioft invariably improve during a courfe of the water, if 
it agrees in the fiiil inllance." The duration of a courfe of 
this water depends in a great degree upon the nature of the 
difeafe under which the patient labours. Thefe obfervations 
upon the effefts of the Malvern water are perhaps equally 
applicable to all fpring-waters of a fimilar degree of 

What has been faid of fpring-waters may be applied per- 
haps with little modification to running waters, which in ge- 
neral differ from _/^7-;H_f -waters only in being fofter, in con- 
taining lefs air, and in being therefore better quahfied for 
many purpofes for which fpring-waters cannot be employed. 
Stagnant waters in general, efpecially in marfhy countries and 
hot chmates, are ufually efteemed unwholelome, and per- 
haps defervedly fo. This arifes chiefly from the large quan- 
tity of vegetable and animal cxuvise which they contain, and 
perhaps from other circumftances of which we are at prefent 
ignorant. They (hould never be ufed, therefore, till they 
have been boiled and filtered ; by which proceffes moft of 
the foreign fubftances will be probably removed. In gene- 
ral ftagnant waters, as Dr. Saunders obferves, are unpa- 
latable ; and this circumflance has probably cauled them to 
be fometimes in worfe credit than they aftually deferve to be 
on the fcore of falubrity. 

2. Simple Jaline Waters. — Under this denomination 
we include all thofe waters impregnated with neutral, 
alkahne, and earthy falls only. Waters of this defcrip- 
tion may be arranged under the following heads : — 
a. Brines, or waters whofe principal faline ingredients are 
the muriates of foda and magnefia ; and b. Bitterns, or waters 
containing principally the fulphates of foda and mag- 

a. Sea-water, which may be confidered as an example of 
the faline waters termed brines, is one of the moll abundant 
andextenfively diffulied compounds occurring upon our globe. 
When taken up at a confiderable diftance from the (hore it 
is quite tranfparent and colourlefs, and free from any fmell. 
Its talle is llroiigly laline, and at the fame time naufeous and 
bitter. When kept for a fhort time it becomes highly of- 
fenfive, from the putrefattion of the animal and vegetable 
matters which it liolds in folution. Its fpecific gravity varies 
in different latitudes and circumllances, but may be faid to 
lie between 1.0269 and 1.0285. "^^^ fpecific gravity is faid 
to be lefs within the polar circles than at the tropics, owing 
probably to the vaft quantities of ice found in thofe regions. 
The waters of inland leas alfo, that have little conneftion 
with the ocean, and the water of bays, &c. into which frelh- 
water rivers empty thenrl'elves, contain in general lefs faline 
matters than the open ocean. This is particularly the cafe 
with the Baltic, efpecially when the wind blows from the 
eaft. The Mediterranean fea, on the contrary, is faid 
to be more faline than the Atlantic. Water taken from a 
confiderable depth is more faline than that taken from the 
furface, particularly after much rain, for rain-water being 
lighter appears to move upon the furface for a confiderable 
time before it becomes quite incorporated. The quantity of 
faline matter alio is ilated to be greater in fummer than in win- 
ter. The water of the Britifh coafts is faid to contain upon 
an average about one-thirtieth of its weight of faline matter, 
and its temperature to vary between 40° and 65°. Sea-water 
does not freeze till cooled down to 28.°^. The following 
is one of the lateft analyfes of fea-water by Dr. Murray. A 

wine pint of water colleftedin the Firth of Forth was found 

to contain 


Ofhme - . . . 2.9 

Magnefia - - - - 14.8 

Soda . - . . ()6,j 

Sulphuric acid - . . i^.^ 

Muriatic acid ... gj,-j 


Or, fuppofing the elements to be combined in the modes 
in which they are obtained by evaporation ; that is, as mu- 
riate of foda, muriate of magnefia, fulphate of magnefia, 
and fulphate of hme, the proportions of thefe falts in a pint 
will be, 

Muriate of foda ... 1B0.5 

of magnefia - - 23.0 

Sulphate of magnefia - . 15.5 
of lime - - - 7.1 


Or, fuppofing that the lime exifts as muriate of lime, 
(which is the moft probable conclufion with regard to it); 
and farther, fuppofing that the fulphuric acid exifts in the 
ftate of fulphate of magnefia, the proportions will be, 

Muriate of foda 

of magnefia 

of lime 

Sulphate of magnefia 






Or, laftly, fuppofing that the fulphuric acid exifts in 
the ftate of fulphate of ioda, the proportions will be, 


Muriate of foda ... i59'3 

of magnefia - - 35.5 

of lime - - - 5.7 

Sulphate of foda - - - 25.6 


The bitter tafte of fea-water is owing chiefly to the mu- 
riate of magnefia which it contains. It may alfo arife, in 
part, from the prefence of decayed vegetable and animal 
fubftances. See the articles Salt, Saltness, and Sea. 

Many attempts have been made to render fea-water po- 
table. Of thefe the beft, and indeed the only good one, is 

The method of obtaining frefli water from the diftillation 
of fea-water was praftifed by fir R. Hawkins, in the reign 
of queen Elizabeth, who thus obtained water that was 
wholefome and nourifhing. See Purchas's CoUeft. of 
Voyages, book vii. chap. 5. 

Experiments were afterwards made by Hales, Lifter, 
Hanton, Lind, and others, to fimplify and render more per. 
feft the procefs of diftillation, and af length it attained a 
great degree of perfeftion, both in France and England. 
Thus M. de Bougainville, in his Voyage round the World, 
bore ample teftimony to the utihty of the machine for dif- 
tilling fea-water, which had been made public in 1763 by 
M. Poiffonnier, its inventor ; and lord Mnlgrave, in his 



Voyage towards the North Pole, in 1773, did equal juftice 
to the method of obtaiiiincj frefh water from the fea by dif- 
tiUation, which had been introduced into the EngUni navy 
in 1770, by Dr. Irving, and for which he obtsined a parlia- 
mentary reward of 5000/. 1 /.• , 

Dr. Irving's contrivance oonfifted in converting the (hip s 
kettle into a Hill. Ev'ery (hip's kettle is divided into two 
parts, by a partition in the middle ; one of thefe parts is 
only in life when peas or oatmeal are drelTed, but water is at 
the fame time kept in the other, to prefnvc its bottom. 
Dr. Irving availed himfelf of this circumllance ; and by fill- 
ing the fpare part of the copper with fea-water, and fitti.ig 
on the lid and tube, (hewed that fixty gallons of frelh water 
could be drawn off, during the boiling of cither of the above- 
mentioned provifions, without the ufe of any additional fuel. 
He recommended alfo the preferving of the diftilled 
from the coppers in which peas, oatmeal, or pudding, are 
dreffed, as both a falutary beverage for the fcoibutic, and 
the moft proper kind of water for the boiling of fait pro- 
vifions. Dr. Irving particularly direded that only three- 
fourths of the fea-water (houUl be dillilied, as the water dif- 
tilled from the remaining concentrated brine was found to 
have a difagreeable tafte ; and as tlic farther continuation of 
the diftillation proved injurious to the veffels. For an ac- 
count of the feveral experiments made on fome of the bed 
diftilled water, prepared by Dr. Irving from fea-water, by 
Dr. Watfon, fee his Chem. E(r. vol. ii. p. 168, &c. 

The (hips of difcovery lately fent out by the French go- 
vernment are furnilhed with an economical didilling appa- 
ratus, and inftead of water have taken with them a fupply 
of fuel. 

Dr. Prieftley fuggefted a plan to give to diftilled water 
the brilknefs and fpirit of fre(h fpring-water, and at the 
fame time to render it, perhaps, a remedy or preventive 
againft the fcurvy, by impregnating it with carbonic acid 
gas. Diftilled water alfo acquires, in a conliderable degree, 
the grateful flavour of common water, by fimple expofure 
for (ome time to the atmofphere. 

Sea-water may be likewife rendered potable by converting 
it into ice. In the polar regions, therefore, there can be no 
want of frefh water. In warm climates, the ingenious freez- 
ing apparatus of Mr. Leflie may be employed to procure a 
fupply of fre(h water from the ocean. 

*. As an example of the bitterns we may feleft the Sedlitz 
•water, which is one of the beft known, and ftrongeft of this 
defcription of fimple faline waters. Sedlitz is a village in 
Bohemia, and its waters, as well as thofe of Seydfchutz in 
the immediate neighbourhood, and which clofely refemble 
them, were firft brought into note about a century ago by 
the celebrated Bergman. The tafte of thefe waters is 
ftrongly bitter and faline, but not in the leaft bri(k or aci- 
dulous, as they ufually contain a fmall proportion of gafcous 
matters. Thus the Seydfchutz water above-mentioned was 
found by Bergman to yield only 6 per cent, of gafeous pro- 
dufts, two-thirds of which only were carbonic acid. Its 
fpeci{ic gravity, as ftated by the fame chemift, is 1.O06, and 
an £ngli(b wine pint was found to contain of 

Carbonate of lime - - .944 

Sulphate of lime - - 5.>40 

Carbonate of magnefia - - 2.6zz 

Muriate of magnefia - - 4*5^7 

Sulphate of magnefia - - 180.497 


Sulphate of foda is not mentioned as an ingredient 
in this water, although it doubtlcfs exifts in it ; at Icaft 
this fait almoft always occurs in waters of this defcrip- 

MeJiitia! Properties and U/es of the Jimple faline Waters. — 
All waters of this defcription aft more or lefs ftrongly upon 
the bowels, according to the quantity of faline ingredients 
which they contain ; hence they are often of the gieateft ufe 
in complaints wlicre alvine evacuations are particularly indi- 
cated. They generally aft alfo as diuretics. Sea-water and 
all brines have the property of inducing a fenfation of thirft. 
" Sta-water," fays Dr. Saunders, " when ufed internally, 
(hould be taken in fuch dofes as to prove moderately purga- 
tive, tlie iiiarcafe ot this evacuation being the peculiar objeft 
for which it is employed : about a pint is generally fuffi- 
cient, and this (hould be taken in the morning, at two dofes, 
with an interval of about half an hour between each. It is 
feldom necelTary to repeat the dofe at any other time of the 
day. This quantity contains half an ounce of purgative fait, 
of which about three-fourths are muriate of foda." — " There 
is very little danger ever to be apprehended from an excef- 
five dofe of fea-water, except the inconvenience of a tem- 
porary diarrhoea, and fometimes a forenefs at the extremity 
ot the reftum, which all fahne purgatives are now and then 
apt to produce." The internal ufe of fea-water, befides its 
general ufe in difeafcs where cathartics are indicated, has 
been recommended in various forms of fcrofulous affeftion, 
efpecially in indolent glandular tumours in the neck and 
other parts, which are commonly (low in ulcerating and in 
their cure ; alfo in deep-fcated fcrofulous inflammations, fol- 
lowed by caries of the bones, profufe difcharges, and tedious 
exfoliation, and particularly in fcrofulous ophthalmia. " In 
all fuch cafes, the internal ufe of fea-water is almoft entirely 
confined to thofe periods of the difcafe when there is no 
general fever and heftic tendency, when no fymptoms of 
danger are prefent, and when the objeft is rather to prevent 
a relapfe than oppofe any prefent difeafe. The external 
ufe of fea-water either as a general cold bath, or as a topical 
application to indolent fwellings, orgranuKiting ulcers, when 
the healing procefs has commenced, coincides perfeftly well 
in thefe cafes with the general intention." The moll im- 
portant advantages of fea-water are indeed probably derived 
from its external ufe as a bath. (See the articles Bath and 
Bathing. ) With refpeft to the medicinal properties of the 
bitterns, we (hall attempt to illuftrate them by relating thofe 
of the Sedlitz water, which wc before felefted as an ex- 
ample of the whole tribe. A pint of this water, taken in 
divided portions, is generally a full dofe for an adult, and the 
ftrongeft perfon feldom requires more than two pints. It 
operates very fpeedily, and without producing griping or 
flatulency; and is ftated by Hoffmann, as quoted by Dr. 
Saunders, to be of the utmoft advantage in a foul llate of the 
ftomach, and general torpor of the inteftinal canal, as it not 
only ftimulatcs thefe organs to expel their morbid contents, 
but by its bitternefs reftores their tone, and with it the appetite 
and digeftive powers. " When theprefcnccof hypochondriafis 
is marked by anxiety, general languor, perturbed dreams, 
a livid hue on the face, difficulty of breathing, pain of 
the back and head, vertigo and coldnefs of the extremities ; 
when a bilious humour and a depraved fecretion of the fto- 
mach impairs its tone and healthy aftion, and is attended 
with obftinate coftivcncfs ; this water, by evacuating its con- 
tents and rcftoring the due force of contraftion, enables it to 
throwoffthe offending matter." — »' Numerous trials alfo have 
(hewn the efficacy of this faline water in that cachexy of fe- 
males attended with a fupprcfilon of the mcnftruol diicharge, 



whereby are produced a general languor, difficult refpira- 
tion, febrile heat and irritation, wafting of the body, and lofs 
of appetite. Alfo when women have arrived at that time of 
life when this periodical evacuation begins to ceafe, and is 
fucceeded by a number of anomalous diforders, fuch as prof- 
tration of appetite, flatulent pains, irregular flufhings, pains 
in the back and fwelling of the feet, a courfe of Sedlitz 
water rellores the wavering appetite, and difperfes the tu- 
mours and other morbid fymptoms. Men of from forty to 
fifty years of age, who have led a very fedentary life, and have 
been accuftomed to intcnfe thouglit and profound medita- 
tion, become frequently afFefted with ocdematous tumours 
in the extremities, a want of due attion in the ftomach, eruc- 
tations after taking food, and a generally impaired ftate 
of health ; all of which are for the moft part very certainly 
removed by a liberal ufe of this water. Perfons alfo of a 
plethoric habit of body, who from fome obftruftion of blood 
in the abdominal vifcera, and have acquired a (Irong difpofition 
to haemorrhoidal affeftions, become thereby often expofed 
to very ferious evils. To fuch perfons a faline water hke 
that of Sedlitz is often of great utility, efpecially if accom- 
panied by blood-letting when requifite, and a general anti- 
phlogiilic plan of cure. Another important ufe of thefe 
■ waters is in removing from th-; fyftem thofe impurities and 
acrid humours which are ufually termed fcorbutic." Such 
are the properties of the Sedlitz faline waters according 
to the celebrated Hoffmann, whofe account, as quoted by 
Dr. Saunders, we have extrafted, becaufe it prcfents in few 
words a comprehenfive and rational view of the medicinal 
properties of this important tribe of waters in general. We 
wi(h however to obferve, that when the ftomach is in a very 
weak ftate, and dyfpepfia is prefent in a very great degree, 
faline purgatives and waters in general may do harm by in- 
creafing thefe affeftions ; their ufe, therefore, in fuch cafes is 
rather contra-indicated, or at leaft fhould be combined with 
otlier remedies calculated to invigorate thefe organs, efpe- 
cially chalybeates. 

3. Simple chalybeate Waters. — Chalybeate waters are either 
Jimple or compound. Under this head oi Jlmple we 
include all waters whofe charafteriftic ingredient is one or 
more of the neutral faltsof iron. Thefe may be confidered 
as of two general defcriptions :— a. Waters containing the 
carbonate of iron, without any ftriking excefs of carbonic 
acid ; and h. Waters containing the fulphate or muriate of 
iron, generally in combination with a large proportion of the 
fulphate of alumina. Waters of thislaft defcription are much 
more rare than the former, and are ufually formed from the 
decompofition of iron pyrites. 

a. As an example of the firft of thefe varieties of fimple 
chalybeate waters, we may adduce that of Tunbridge Wells. 
This water has been lately fubmitted to a careful and ac- 
curate analyfis by Dr. Scudamore, from whofe pamphlet on 
the fubjeft we chiefly take the following account. The 
temperature of the fprmg throughout the year is uniformly 
50° ; and its fp. gr. in the month of Auguft, at its natural 
temperature, was 1.0007. The frefli water is perfeAly 
tranfparent, and does not fend forth air-bubbles. It exhales 
a fmell which is diftinAIy chalybeate. Its tafte in this refpedl 
is ftrongly marked, but is neither acidulous nor faline. It 
has an agreeable frefhnefs, and is by no means unpalatable. 
Submitted to analyfis, one gallon was found to contain, 

Cubic Inches. 
Of carbonic acid - - - 8.0J 

Oxygen - - - - .50 

Azote - .... 4.7^ 

Of muriate of foda 
— of lime 

; of magnefia 

Sulphate of lime 
Carbonate of lime 
Oxyd of iron 

Traces of manganefe, infoluble mat-'j 
ter (vegetable fibre, filex, &c. ) 1 
Lofs in procefles 







Or, ftating the refults according to Dr. Murray's view, 
which will be particularly explained when we treat of 
the analyfis of mineral vraters, the following ettimate will 
appear : 

Muriate of foda . . - 1.25 

Sulphate of foda ... i.^y 
Muriate of lime - . . i,^± 

of magnefia . . .29 

Carbonate of hme . . .27 

Oxyd of iron - - . 2.29 

Traces of manganefe, &c. - . .44 

Lofs, &c. • • - - .13 


This latter eftimate, which renders the carbonate of iron 
the moft abundant ingredient in the water, appears much 
more probable than the former, and to account more fatif. 
fatlorily for its medicinal effefts. 

b. One of the moft ftriking examples of the fecond variety 
of fimple chalybeate waters is that occurring in the Ifle of 
Wight, and lately analyfed by Dr. Marcet. This fpring iffues 
from a chff' on the S.S. W. fide of the ifie, immediately under 
St. Catherine's Down, in the parifti of Chale, between which 
village and the village of Niton it is nearly equidiftant. The 
diftance from the fea-ftiore is about 150 yards, and elevation 
about 1 30 feet above the level of the fea. Its properties, &c. 
are the following: — When it firft iflTues from the rock it is per- 
fectly tranfparent, and remains fo if kept in clofe veflels ; 
but when expofed to the air, reddifh flakes are foon depo- 
fited in it. It has a flight chalybeate fmell, and a highly 
aftringent and ftyptic tafte. Its fpeciftc gravity, in a courfe 
of feveral experiments, was found to be 1007.5. ^"^ P'"^ 
or fixteen-ounce meafures yielded 

Of carbonic acid -rVths of a cubic inch, 

Sulphate of iron, in the ftate of cryftal-l 

lized green fulphate - . . j ^ ■4- 

Sulphate of alumina, a quantity of which, \ 

if brought to the ftate of cryftallized > 31.6 
alum, would amount to . -J 

Sulphate of lime dried at 160°, - . 10. i 

Sulphate of magnefia cryftaUized - 3.6 

Sulphate of foda cryftallized - - i6.0 

Muriate of foda cryftaUized ... 4.0 






This therefore is the ftrongeft aluminous chalybeate known. 

Medicinal Properties and Ufes of Jimple chalybeate Waters.^ 

a. The feafon for drinking the Tunbridge water, which we 

have felefted as an example of the fimple carbonated cha- 

C lybeates, 


lybeatcs, is ufually from May to November. On entering 
upon the ufe of this water fome aperient (hould be prcmifed ; 
and Dr. Scudamore recommends that the firft dofe (hould 
be taken at feven or eight o'clock in the morning, the 
fecond at noon, and the third about three in the afternoon. 
The exaft quantity to be taken muft be varied according 
to circumftanccs ; but " as a general ftatement," fays Dr. S., 
" I would fay that half a pmt daily is the extreme fmalleft. 
quantity, and that two pints daily is the extreme largeft 
amount to found a jull expcAation of benefit ; and further, 
in the way of general outline of dircAion, I conceive that 
half a pint, a pint, a pint and a half, and two pints, fhould 
form the progreflive ratio of the total daily quantity to be 
taken at the three intervals. As the patient arrives at the 
larger proportions, they may with advantage be fubdivided 
with the interval of a quarter or half an hour, which (hould 
be occupied in exercife." Tea at breakfaft is direAed to be 
avoided ; and in cafes when the water difagrees at its natural 
temperature, it is recommended to be adminiftered warm. 
•' On the firft employment of the water, either cold or warm, 
fome inconvenient fenfations very commonly arife, fuch as 
fluftiing of the face, (light fulncfs of the head, with drowCnefs 
and an uneafy diftenfion of the ftomach, together with con- 
tinued flatulence. In general thefe effefts are not of im- 
portance, either in degree or duration, and are much to be 
prevented by previous attention to the ftomach and bowels." 
— " As a general ftatement, it may be added, that the employ- 
ment of this water is improper in a very plethoric ftate of the 
circulation ; alfo when there is an inflammatory determination 
to any particular organ, or even when local congeftion exifts 
without inflammation. In cafes of fimple debility of the con- 
ftitution, the water promifes to produce its happieft e(fefts. 
The proofs of its immediately agreeing with the patient are 
increafed appetite and fpirits, and thefe aufpicious fymptoms 
are followed by a gradual improvement in the general en- 
ergy and ftrcngth." The bowels ufually become confti- 
pated under its ufe, and require the afTiftance of medicine. 
The warm batli is occafionally of fervice in conjunftion with 
this water, as was long ago pointed out by Hoffmann. 
Exercife alfo after its ufe is generally of great importance. 
In dyfpepfia depending on dcbihty of the ftomach, and ac- 
companied with general languor and nervoufnefs, this water 
is remarkably reftorative. In uterine debility alfo, and chlo- 
rofis, its ufe is often of the utmoft fervice. It has been much 
recommended hkewife in fome cutaneous affeftions. For the 

complaints of children, efpecially when young, (tliat is to fay, 
under fix or feven years of age, ) it is not in general adapted, 
for reafons fufficiently obvious. A courfe of this water may 
vary from three weeks to two or three months, according to 
circumftanccs. b. With refpcA to the medicinal properties 
of waters containing the fulphatcs of iron and alumina, as the 
Ifle of Wight and HartfeU waters above-mentioned, they 
differ little perhaps, except in degree, from thofe of the 
fimple chalybeate waters. The Kle of Wight water is fo 
ftrong, that it is always proper to dilute it at firft with twice 
its quantity of common water ; and even then the dofe cannot 
well exceed two or three ounces, which may be gradually 
increafed to about a pint in twenty-four hours. Dr. Saun- 
ders recommends the fame quantity as the maximum dofe of 
the HartfiU water. Both thefe waters are often much im- 
proved by being gently heated, efpecially in cafes where the 
ftomach is very delicate and irritable. Dr. Lempriere, who 
has written a pamphlet on the Ifle of Wight water, ftates, 
tiial he found it particularly ferviceable in the debility in- 
duced by the Walcheren fever, chronic dyfentery, &c. as 
well as in every inftance when the conftitution had been 
undermined by previous lUnefs, and the ordinary tonics had 
failed. It is particularly neceffary to guard againft coftive- 
nefs during the ufe of thele waters. 

Compound Chalybeate Waters. — Thefe may be divided into 
a. Saline chalybeates, and b. jlcidulom chalybeates. 

a. The Cheltenham waters, properly fo called, are a good 
example of the faline chalybeates. ( For the liiftory of thefe 
waters, fee Cheltenham. ) Since that article was written, 
however, feveral fprings of different quahties and powers 
have been difcovercd by Mr. Thomion ; an abftraft of the 
compofition and properties of which, as lately publi(hed, we 
(hall now take the opportunity of laying before our readers. 

The fprings which have been defcribcd and analyfed by 
Meffrs. Brande and Parkes are fix, viz. 

1. The ftrong chalybeate faline water. Sp. gr. 1009.2. 

2. The ftrong fulphurettcd faline water. Sp. gr. 1008.5. 

3. The weak fulphuretted faline water. Sp. gr. 1006. 

4. The pure faline water. Sp. gr. 1010. 

5. The fulphuretted and chalybeated magnefia fpring, or 
bitter faline water. Sp. gr. ico8. 

6. Saline chalybeate, drawn from the well near the 

The following Table prefcnts a view of the contents of a 
wine pint of thefe different fprings. 








Muriate of foda 

Muriate of magnefia . . . . - 
Sulphate of foda ...... 

Sulphate of magnefia - 

Sulphate of lime 

Carbonate of foda ...... 

Oxyd of iron ...... 

Lofs ......-- 


Sulphuretted hydrogen 

Carbonic acid - - - - - - . - 























1 0.0 









Cub. In. 

Cub. In. 



Cub. In. 


Cub. In. 

Cub. In. 



Cub. In 









The medicinal properties ol thefe different (pr'mgs of courk magnefia and iron in brown cryilals, highly tonic; fub- 

vary according to their compofition and ftrength. Mr. carbonate of magnefia in powder, and calcined magnefia. 

Thomfon, the proprietor, procures from them fix different i. As an example of the acidulous chalybeates, we may ad- 

faline preparations, neither of which, however, is precifely duce the celebrated waters of Spa. (See Spa.) Dr. Jones 

fimilar to the water drank at the fpa. Thefe he denomi- has lately publilhed an interefting paper on thefe waters, 

nates, cryftallized alkaline fulphates ; ditto eiBorefced and which contains, among other things, analyfes of the different 

ground to an impalpable powder for hot climates ; magne- fprings, of the refults of which the following table prefents 

fian fulphate in a ftate of efflorefcence ; a murio-fulphate of a fummary view. 

Table exhibiting the Nature and Proportion of the Subftances contained in One Gallon of the refpeftive Spa Waters. 

Fountains. ralnrc. 


Acid Gas. 
Cub. In. 


of Soda. 

of Soda. 

of Soda. 

of Lime. 

of Mag- 

Oxyd of 






1. 0009 S 








































Groefbeeck - 














I ft Tonnelet - 








1. 10 






2d Tonnelet - 







0. 10 







Watroz - 

not afcer- 










The Pouhon,T 
after much > 
wet weather. J 











* Quantity not appretjable. 

With refpeft to the medicinal properties of the compound 
chalybeates, they are, as might be expetted, of a mixed cha- 
rafter, and ufually correfpond with the nature of the pre- 
dominant impregnating ingredients ; hence their proper- 
ties will be readily underftood from what has been ad- 
vanced. For further particulars refpefting the medicinal 
properties of the Cheltenham and Spa waters, we refer 
our readers to thefe articles. 

4. Simple Acidulous Waters. — Under this denomination 
may be included all waters whofe charafteriftic ingredient is 
an acid. They may be confidered as of two defcriptions : 
a. Thofe impregnated with a volatile acid, as the carbonic 
and fulphurous acids ; and b. Thofe containing a fixed acid, 
as the muriatic and fulphuric acids. 

a. The waters of Seltzer may be adduced as an example 
of the firft variety of acidulous waters. " Seltzer is a village 
fituated in a fine woody country, aboat ten miles from 
Frankfort, and thirty-fix from Coblentz, in a diftricl which 
abounds with valuable mineral fprings." This water has 
been examined by Hoffmann, Bergman, and others. When 
frefh from the weU, it is perfectly clear and pellucid, and 
fparkles much when poured into a glais. Its tafte is flight- 
ly pungent, but at the fame time gently faline and alka- 
line. On expofure to the aii- for a fhort time, the carbonic 
acid efcapes, and the alkaline tafte becomes more per- 

ceptible. According to Bergman, an Englifh pint con- 
tains of 

Carbonic acid upwards of 

Cub. Inche 

Carbonate of hme about 
Carbonate of magnefia 
Carbonate of foda 
Muriate of foda 


- 17.5 


b. Waters containing a free mineral acid in excefs are 
very rare, and chiefly confined to volcanic countries. Mr. 
Garden has lately examined a water of this defcription from 
White ifland, on the coaft of New Zealand : it was of a pale 
yellowifh-green colour ; its odour i-efembled that of a mix- 
ture of muriatic and fulphurous acids. Its tafte was 
ftrongly acid and ftyptic, like that of a chalybeate. Its 
fpecific gravity 1.073. On being fubmitted to analyfis, its 
contents were found to contift chiefly of muriatic acid, a 
flight trace of fulphur, fmall proportions of alum, muriate 
of iron, and fulphate of lime. Waters impregnated with 
C 2 fulphuric 


I'ulphuric acid are fomctimcs met with likewife in tlic vi- cific gravity is 1.0064. A wine pint, according to the ex- 
cinity of volcanoes. periments of the fame chemift, was found to contain about 

Of fulpliuretted hydrogen 
Carbonic acid gas 

And of 


As to the medicinal propertiet of thefe waters, they pro- 
bably differ little from thofe of a dilute folution of the dif- 
ferent acids which they contain. For the particular pro- 
perties of the Seltzer water, fee Sei.tzf.r. 

Compound Adduloiis /^a/fr/.— Acidulous waters fome- 
times contain fo large a proportion of faliiie matters, that the 
nature of their operation is coiifiderably modified. Such 
waters may be denominated faline acidulous waters. The 
nature of their compofition and medicinal properties will be 
readily underftood from what has been already advanced. 

5. Sulphureous ll'alcrs. — Thvic Vii-^ e\thcT Jimple or com- 
piunJ. A good example of a Jimpk fulphureous water is 
the Moffat fpring. The village of Moffat is fituated in 
Dumfriesfhire, on the banks of the Annan, about fifty 
miles fouth-wefl of Edinburgh. The fiilphnreous waters 
for which thii village is noted, iffue from a rock a little 
below a bog, whence, fays Dr. Saunders, they probably de- 
rive their fulphureous ingredient. This water, even when , , . ^ 

firft drawn, appears fomewhat milky. Its tafle is ful- With refpeft to th& mtdtcinal properltes ot v/ittrs of this 
phureous, and flightly fahne. It fp.irkles a little when defcription, and particularly of Harrowgate water, they are 
poured from one gfafs into another. Ob expofure to the air, of the greateft ufe in all thofe complaints that require pur- 
it becomes more turbid, and ilirows up a thin film, which is gatives, and at the fame time are benefited by fulphur ; 
pure fulphur, and it thus lofes its diftiiiguilhing properties as hence they have been long celebrated in cutaneous affec- 
a fulphureous fpring. This change even takes place in clofe tions, in piles, worms, &c. They have alfo been found of 
wfTels, fo that it cannot be exported with any advantage, great ufe in that obflinatcly coftive habit of body which 

Muriate of foda 
Muriate of hme 
Muriate of magnef.a 
Carbonate of lime 
Carbonate of magnefia - 
Sulphate of magnefia 

Cubic InchK. 









According to Dr. Cirnctt's analyfis, a wine pint of this 
water contains 

Of fulphuretted hjdrogen 
Of carbonic acid 
Of azote 


K l„c!,es 




ufually accompanies hypochondriafis. Harrowgate waters 
were formerly principally applied externally, but now they 
are generally recommended to be taken internally, in fuch 
dofes as to produce a fenfible effeft upon the bowels ; for 
which purpofe it is commonly neceffary to take in the morn- 
ing three or four glaffes, of rather more than half a pint 
each, at moderate intervals. 

6. Thermal Healers. — There is fomething fo myllerious 
and remarkable in the circum fiances of thermal fprings, that 
they have in :J1 ages attraftcd great attention, and been fup- 
And of muriate of foda 4.4 grains. Po^ed to polTefs extraordinary medicinal properties. Hence, 

by moft writers on mineral waters, thermal fprings have 
With refpeA to the medicinal properliesof fui-iple fulphureous been arranged under a diftinft head ; and as there appears to 
waters, they have been always celebrated for their good be no ferious objcdion to this arrangement, we have thought 
efFeAs in cutaneous affeAions in general, and alfo in fcro- proper to adopt it. The invefligation of the cau/e of 
fula. They are applied externally in the form of a warm thermal fprings belongs to the geologift, and will be found 
bath, as well as taken internally. They have been alfo re- under Earth, Hot Springs, Temperatuhe, Volcano, 
commended in bihous complaints, dyfpepfia, general want and analogous articles. 

of aftion in the alimentary canal, and calculous cafes. The They may be divided 'm\.o Jjmple and compound. 

quantity of the Moffat waters ufually prefcribed internally Simple thermal waters are either lepid, that is, pofrefTing a 
varies /rom one to three bottles every morning. But Dr. temperature below that of the human body ; or warm, pof- 
Saunders jullly obfervcs,that few delicate flomachs can bear feffing a temperature above that point. A good example of 
fo much. On the other hand, the fame eminent phyfician in- the fimple tepid waters are thofe of Buxton. ( See Bl XTON 
forms us, that the common people not unfrequently fwal- Water.) Ti/xV/ waters ufually occur in lime-flone liiilrifts. 
low from fix to ten Englilh quarts in one morning. IVarm waters of every degree of temperature, even to the boil- 

For further particulars refpeding this fpring, fee ing point, are occafionaUy met with in the neighbourhood of 
Moffat. volcanoes. See Volcano. 

Sulphureous ivalers frequently contain fo coiifiderable a With refpeft to the medicinal properties of the fimple 
proportion of faline fnbflanccs as to merit the name of com- thermal vi'aters, it is ixtreinely doubtful if they pofTefs any 
pound. An example of fuch waters we have in the cele- other powers than thofe of common water artificially raifed 
bratcdfpringsof Harrowgate, in Yorkfhire. (See Harrow- to the fame temperature. 

GATE. ) This water, when firll taken up, appears perfedly Thermal fprings are liable to be impregnated with all the 
clear and tranfparent. It emits a few air-bubbles. Its different fubllanccs which ufually enter into the compofi- 
fmell is very flrong, fuljjhureous, and foetid, fike that of a tion of cold mineral waters ; hence they are ver)- various 
foul gun-barrel. Its talle is bitter, naufeous, and flrongly in their n.iture. Such thermal waters may be called com- 
faline ; though it is remarkable that mofl perfons foon be- pound, and without any great facrifice of the principles of 
come reconciled to it. On expofure to the air, it becomes arrangement we have adopted, may be comprifed under 
turbid, the fulphureous odour is diminifhed, and the fulphur three heads ; namely, a. Saline thermal waters, 6. Acidulo- 
i» gradually depofited. According to Dr. Garnett, its fpe- chalybeate thermal waters, and c. .Sulphureous thermal 

waters ; 


waters ; each of which varieties may be either tepid or 

a. Thermal waters fimply fallne are very rare. Their 
properties can in no refpeft be fuppofed to differ from cold 
faline waters raifed to the fame temperature. Sea-water, 
therefore, heated artificially, is a good example of this 
variety. It is generally ufed externally as a bath. See 

b. A good example of the acidulo-chalybeate thermal 
waters we have in the fprings of Carlfbad. For a full ac- 
count of the chemical properties of tliefe fprings, fee 

c. The celebrated waters of Aix-la-Chapelle, or Aken, 
afford a good example of the fulphureous thermal waters. 
See Aix-la-Chaj-elle. 

With refpeft to the medicinal properties of the compound 
thermal waters, they have all been in much repute as baths, 
which was, perhaps, the original mode in which the two laft 
varieties in particular were employed. In later times, they 
have been much ufed internally. The difeafes, fays Dr. 
Saunders, to the cure of which the internal ufe of Carlfbad 
waters are apphcable, are as various as the nature of their 
foi'eign contents ; and from the union of feveral valuable 
quahties in one water, it may be made ufe of in cafes of very 
oppofite natures, without incurring the ccnfure of employing 
it indifcriminately as an univerfal medicine. In common 
with the other purgative chalybeates, it is found to be emi- 
nently ferviceable in dyfpepfia and other derangements of 
the healthy aftion of the llomach, in obllrudlions of 
the abdominal vifccra, not connefted with great organic 
difeafe, and in defeft or depravation of the biliary fecretion. 
It is alio of ufe in calculous affettions, and is highly efteemed 
for relloring the uterine fyilem to a healthy ftate. The 
fame precautions againft its internal ufe in plethoric and 
irritable habits, and thole who are fubjeft to haemoptyfis, or 
liable to apoplexy, require to be obferved here as with any 
of the other aftive thermal waters. The Aix-la-Chapelle 
waters, taken internally, are likewife found efTentially fer- 
viceable in the numerous fymptoms of diforders in tlie 
ftomach and biliary organs, that follow a life of high indul- 
gence in the luxuries of the table. It alfo much relieves 
painful affeftions of the kidneys and bladder. The fame 
precautions in its ufe are to be attended to, as thofe above- 
mentioned refpetting the Carlfbad waters. For the ex- 
ternal ufes of thcle waters, fee Bathing, and the articles 
Carlsbad and Aix-la-Chapelle, before referred to. 

Our readers will readily perceive, from the above fyfte- 
matic fl<etch, that the infinite variety which exifts among 
mineral waters abfolutely precludes aperfeS arrangement of 
them : we truft, however, that no mineral water can occur 
which may not be referred to one or other of the above 
heads or their fubdivifions, without any great facrifice of 
our principles of arrangement ; and, confequently, whofe 
general medicinal properties cannot be eftimated with tole- 
rable accuracy a priori from its chemical compofition. 

On the general Ufes of Water in a dietetic and medicinal Point 
ofVieiu. — No organic procefs nor interchange of elements 
can be fuppofed to take place without the intervention of a 
fluid ; organized beings, therefore, contain a large propor- 
tion of fluid in their compofition, through the medium of 
which that endlefs feries of changes, effential to their exift- 
ence, is principally effefted. The bails of this fluid is uni- 
verfally water, which of all other fluids is the moft emi- 
nently fitted for difTolving and holding ia folution every 
variety of animal and vegetable matter. See Food of Plants. 

In animals, the firfl great flep in the feries of vital pro- 
ceffes is digijlion; and here nature appears to render the pre. 

fence of a fluid particularly neceffary, in order, as it were, to 
infure for herfelf a fufficiency for her future operations. 
Accordingly, we find that all animals inflinftively take in a 
certain proportion of fluid, either in the form of fimple 
water, or fucculent food. Man alone is the only animal 
accuftomed to fwallow unnatural drinks, or to abufe thofe 
which are natural ; and this is the fruitful fource of a great 
variety of his bodily and mental evils. 

\W know little of the intimate nature of the digeflive 
proctfs, but we know that it is chiefly effefted by means of 
a highly animahzed fluid fecreted by the flomacli itfelf. 
Now this important fluid, by drinking too httle or too 
much, or by other caufes, may be rendered too concentrated 
or too dilute for the due performance of its operations ; and 
dyfpepfia, and all its confequ^nces, may thus enfue from ha- 
bitual errors in the quantity of drink on]y. The remedy in 
fuch cafes is obvious, and confifts perhaps in nothing more 
than in duly regulating the quantity of watery ahment, as 
diftatcd by inftinft, or the fenfation of thirft only. 

An eminent modern phyfiologift recommends to abftain 
from drinking during meals, and for fome time afterwards ; 
and as a general rule, this may, perhaps, be proper, fince a 
healthy flomach may be fuppofed to be always able to fecrete 
fluid enough for its own immediate operations : there can be 
no doubt, however, but many exceptions to this rule may,be 
met with, arifing either from the nature of the food or 
condition of the flomach, in which moderate dilution is not 
only grateful but falutary. 

With lefpcft to the choice of water as an article of diet, 
(for our readers will underiland that we fpeak of water only 
in this place,) thofe which are hard and impure have long 
lain under theimputation of producing calculous affeftions ; 
and we have good authority for ft;ating, that, in many in- 
llances, the ufe of fuch waters aftually increafes the painful 
fymptoms of thefe dillrefTing complaints. It is not perhaps 
an eafy taflc to explain this, fince, with the exception of hme, 
the fubftances found in hard waters never enter into the 
compofition of calculi : their operation, therefore, muft be 
rather of a predifpofing nature, and is probably exerted upon 
the organs of digeflion, which are well known to be inti- 
mately connefted with the kidney. A faft which renders 
this opinion the more probable is, that hard waters are often 
pofitively noxious to irritable fl;omachs,by inducing dyfpepfia. 
In fhort, pure water, as we formerly obferved, mufi: obvionfly 
be much better adapted for the important purpofcs of dilu- 
tion and folution, than water already faturated as it were 
with foreign fubftances ; and upon this principle may pro- 
bably be fatisfaftorily explained the good effefts of Malvern 
and other waters, whofe only charafteriflic property is, 
their remarkable degree of purity. 

In a medicinal point of view, the ufe of water as a diluent 
is moft important ; and, as Dr.Sa.i nders juftly obferves, the 
long Uil of ptifans, decoftions, &c. ufually prefcribe"d by 
phyficians in acute difeafes, owe their virtues alnioft entirely 
to the watery diluent itfel/. 

The inftinftive defires or averfions, continues the fame 
eminent writer, of perfons labouring under any fpecies of 
difordered funftions, have been juftly confidered as deferv- 
ing the higheft; attention from the phyfician, and in moft 
cafes will furnith him with ufeful hints for his treatment of 
the patient. In acute difeafes, the thirft after water is pe- 
cuharly remarked as a charafteriftic fymptom, and is a 
direft inftinftive indication of increafed heat and want of 
dilution ; and this is fo uniform, that the degree of fever 
may often be pretty well eftimated by the eagernefs of the 
fufferer after cold drink. The benefits arifing from large 
dilution in acute difeafes, however, are not confined to the 



mere quenching of third, though this is in itfelf highly ad- 
vantageous ; but it is after fo much liquid is added to the 
circulating mafs, that the truly diluent effaAs arc pro- 
duced. Thefe confill, in Dr. S.'s opinion, in diminilhing 
the morbid heat and violence of reafUon in the folids ; in pre- 
ferring all the fecretory organs in a pervious llate ; and in 
checking that tendency to fpontaneous change, which ren- 
ders the fluids pofitively noxious to the veflels in which they 
are contained, and unfit to perform thofe functions, on which 
the health of the body f j elToniially depends. 

It appears poffible, however, in the opinion of the fame 
author, to carry dilution in active fever to excefs. In 
fever, as is well known, the exhalent veffels are compara- 
tively inaftive, or morbidly conftricled, and the fecretion of 
urine is defedive in quantity. In fuch cafes, it is often 
better to take liquids in fmall divided dofes, which has the 
effeft of moderating tlie third, without overloading the ar- 
terial fydem, and bringing on that tenfion and plenitude 
liable to be produced by fwallowing too large a proportion 
of liquids. 

In the ufe of water in acute difeafes, the temperature 
(hould be particularly attended to. As a general rule it 
may be lafd down, that the temperature of diluents at the 
different periods of a cold, hot, and fweating dage of a fim- 
ple febrile paroxyfm, fhould be hot in the lird cafe, cold in 
the fecond, and tepid in the third ; and it is chiefly in the 
fecond dage that the quantity may be mod liberal. 

Mod of the above remarks are equally applicable to 
the ufe of water in chronic difeafes in general, but more 
efpecially in the deranged funftions of the domach and 
bowels and biliary organs, occafioned by a long and habitual 
indulgence in high food, drong drink, and all the luxuries 
of the table, and which are well known to be fo decidedly 
benefited by the ufe of water as a medicine. As in acute 
difeafes, fo in chronic affedions likewife, it is often of great 
importance to attend to the temperature of the water. A 
draught of cold water, for example, will often induce fick- 
nefs and other didrcding fymptoms m delicate dyfpeptic ha- 
bits, while water rendered (lightly tepid may be taken with 
impunity and even advantage. On the other hand, the ha- 
bitual ufe of warm water or drinks is to be avoided, and 
doubtlefs always does much harm. 

We fliall clofe thefe remarks by a quotation from Dr. 
Saunders on the habitual ufe of water. " Water-drinkers," 
fays this eminent writer, " are in general longer Lvers, are 
lefs fubjeft to decay of the faculties, have better teeth, more 
regular appetites and lefs acrid evacuations, than thofe who 
indulge in a more ftimulating diluent for their common 

For the external ufes of water, fee the articles Bath 
and Bathing, where this part of the fubjeft is treated at 

On the general Contents of Mineral IVatert and their Opera- 
tion The proportions of faline and other ingredients in 

mineral waters are for the mod part fo fmall, as apparently 
to be infufBcient for explaining the effefts they often pro- 
duce upon the animal economy. Many attempts, therefore, 
liavc been made to explain this circumdance by different 
writers, and the fubject is fo intereding, that we cannot let 
it pafs without making a few remarks upon it. 

Dr. Saunders, one of the lated iind bed writers on mine- 
ral water*, very properly ridicules the idea' of fpecijic and 
other myderious properties, by which the older authors at- 
tempted to explain their operation. This intelligent phyfi- 
cian fuppofes, that a very great proportion of their effcfts 
depends fololy upon the diluent operation of the water itfelf. 
Of tliis, aa wc formerly obferved, there can be no doubt, in 

many inftances ; and even in all, the mere bulk and tempera- 
ture of the water mud be allowed to produce a certain pro- 
portion of tlie effefts. Still, however, innumerable inftances 
occur, in which thefe are infufBcient to explain the whole, 
even when aided by the additional circumdance of great 
dilution, on which the above eminent phyfician likewife lays 
great drefs. The matter, therefore, lias always appeared 
iufficiently puzzling, and it is only lately that a httle light 
has been thrown upon it by the ingenious views of Dr. 
Murray, which will be more fully explained in the next 

There can be no doubt that foluble falts in general are 
capable of exerting a much more powerful cffeft upon the 
animal economy, cxteris paribus, than thofe which are info- 
luble. The muriates are the mod foluble clafs of falts oc- 
curring in waters, and are moreover, independently of this, 
the mod aftive ; at lead, this is the cafe with the earthy 
muriates, efpecially the muriate of lime. Now this fait. 
Dr. M. has rendered it probable, exids in all mineral waters 
found by the ufual analytic method to contain the ful- 
phate of lime and muriate of foda, which comprehend by 
far the greater number. The fame ingenious author has 
alfo rendered it probable, that iron not unfrequently exifts 
in the date of muriate indead of carbonate, as commonly 
believed, as for example, in the Bath waters. With thefe 
views in gentral we perfectly coincide, and hax'C no doubt 
that, in many indances, a large proportion of the good ef- 
fects of mineral waters arifes from the muriates they con- 
tain ; but we mud confefs that many difficulties dill appear 
to us to remain on this obfcure fubjed, which cannot, in the 
prefent date of our knowledge, be fatisfaftorily explained. 

Anal^is of Mineral Waters The analyfis of mineral 

waters has been judly deemed one of the mod difficult pro- 
blems in praftical chemidry. This ariles partly from the 
diverfified nature of the ingredients, and partly from the 
minute proportions in which lome of them exid. The cele- 
brated Bergman was the fird chcmift who prefented the 
world with a general method or formula for analyfing mine- 
ral waters. This was edeemed excellent in its day, and 
evcn^at the prefent time may be confidered valuable. Twenty 
years afterwards, Mr. Kirwan publidied an effay on the fub- 
jedt, which not only comprifed all that had been previoufly 
done, but contained many valuable additions made by 
himfelf. He alfo propofed a new method of analyfis, of 
which we diall give a diort account hereafter. 

a. The fird dep in the examination of a mineral water, 
is to notice accurately its fenfible properties, fuch as its tem- 
perature, colour, tranfparency, tade, fmell, &c. 

b. The fecond Rep is to afcertain its fpecific gravity, the 
fpontaneous changes it undergoes on cxpofure to the air, 
the application of heat, &c. 

c. Thefe preliminary operations being performed, the next 
objeft of inquiry, is to endeavour to obtain a knowledge of 
the different ingredients prefent by means of reagents, or tejls, 
as they are ufually termed. We have already mentioned the 
different ingredients commonly met with in mineral waters, 
and diall now proceed to give a lid of the different tejis by 
which their prefence may be detcfted. For this lid we are 
chiefly indebted to Dr. Thomfon, who has compiled it from 
Kirwan and others. 

1 . The Gafemis Suljances may be feparated from water, by 
boihng it in a retort connected with a pneumatic appara- 
tus, and their nature and proportions may be afcertained in 
the manner to be prefcntly delcribed. 

2. Hydrogen and its Compounds. — Sulphuretted hydrofi^cn is 
readily didinguirticd by its peculiar fmell, by its reddening 
litmus fugacioufly, and by its blackening paper dipped in fo- 



Eution of lead. Carbureited hydrogen may be detefted by 
its inflammable nature, and by it3 yielding carbonic acid by 
combuflion. Phofphurettcd hydrogen may be known by its 
peculiar fmell and fpontaneous inflammability. 

3. Atmofphertc Air : Oxygen and Azote The prefence 

of oxygen gas may be known by its power of fupporting 
combullion, and by the diminution which takes place on 
mixing it with nitrous gas or phofphorus. There is no 
teft for azote, but it is fufficiently charafterized by its ne- 
gative properties. 

4. AHalies and Alkaline Earths. — The alialies and alkaline 
earths, as well as their carbonates, are diftinguifhed in general 
by the following lefts. Turmeric paper is rendered brown 
by alkalies, or reddifh-brown, if the quantity be minute. 
Brazil wood is rendered blue not only by the alkalies, but alfo 
by the alkaline and earthy carbonates. Litmus paper reddened 
by vinegar is reftored to its original colour by alkalies, and 
alio by the alkaline and earthy carbonates. If thefe changes 
are fugacious, we may conclude that the alkali is ammonia. 
Fixed 3\k2Xies are indicated when a precipitate is produced by 
muriate of magnefia after being boiled. The •volatile alkali, 
or ammonia, may be readily diftinguifhed by its fenfible 
properties. The earthy and metallic carbonates are precipi- 
tated by boiling the water containing them, except carbo- 
nate of magnefia, which is only precipitated imperfeftly. 
With refpeft to the individual fubftances of this clafs — 
Potajh may be diftinguiftied by the precipitate it produces 
virith the muriate of platina, the fulphate of alumina, and 
tartaric acid. Tor foJa there is no good teft, but its falts are 
eafdy diftinguiftied from thofe of potafti. Ammonia may be 
known from its odour and other properties above-mentioned. 
I^ime is detefted by means of the oxalic acid, which occa- 
fions a white precipitate. To render its operation certain, 
however, the mineral acids, if prefent, muil be faturated with 
an alkali. Magnefia and alumina. Pure ammonia precipi- 
tates both thefe earths and no other, provided the carbonic 
acid has been previoufly feparated. Lime-water alfo pre- 
cipitates only thefe two earths, provided the carbonic and 
fulphuric acids be previoufly removed. The alumina may 
be feparated from the magnefia by boiling the precipitate in 
pure potafh, which diffolvcs the alumina and leaves the mag- 
nefia. Silica may be afcertained by evaporating a portion of 
the water to drynefs, and rediffolving the precipitate in 
muriatic acid. TheJiUca remains behind undiflblved. 

5. Metals. — The prefence of metals may be fufpefted, if 
precipitates are produced by the prufliate of potafh and ful- 
phuretted hydrogen. Iron may be difcovered by the follow- 
ing tefts. The addition of tinfture of nut-galls gives water 
containing iron a purple or black colour. If the tinfture 
has no effeft upon the water after boiling, though it co- 
loured it before, the iron is in a ftate of carbonate. Pruf- 
liate of potafti produces a fine blue precipitate in water 
containing iron, provided no excefs of alkali be prefent, 
which muft be faturated with an acid. Manganefe is occa- 
fionaUy prefent in minute quantity, efpecially in chalybeate 
waters. It may be precipitated by ammonia with proper 
precaution, and is known by the beautiful violet hue it im- 
parts to borax, on being fufed with that fubftance. Copper 
is occafionally met with in waters. It may be detefted by 
the fine blue colour produced on the addition of ammonia ; 
by the red-coloured precipitate produced by the prufliate 
of potafti ; or it may be obtained in the metallic ftate by 
plunging into the water a piece of polifhed iron. Lead 
IS fometimes found in waters that have traverfed leaden 
pipes. Such waters are blackened by a curj-ent of fulphu- 
retted hydrogen gas ; but to render the prefence of the metal 

more certain, a portion of the water is to be evaporated to 
drynefs ; the remainder is to be tefted with nitric acid, and 
afterwards tefted with folutions of the carbonate and ful- 
phate of potafti, which produce white precipitates, from 
which the lead may be readily obtained in the metallic 

6. Acids — Carbonic acid, in a iise or uncombined ftate, 
may be detefted by lime-water, which occafions a precipi- 
tate foluble with effervefcence in muriatic acid ; or by the 
infufion of litmus, which is reddened, but becomes again 
blue on expofure to the air. Water containing free car- 
bonic acid lofes this property of reddening litmus by boil- 
ing. The fulphuric acid is readily diftinguifhed by the 
muriate, nitrate, or acetate of barytes, ftrontian, and lime, 
and alfo by the nitrate er acetate of lead. The moft deh- 
cate of thefe tefts is the muriate of barytes : this pro- 
duces a white precipitate, infoluble in muriatic acid. 
To enfure the operation of this teft, it is neCeffary 
that no earthy or alkaline combination be prefent in the 
water. The muriatic acid is detefted by the nitrate of 
filver, which occafions a white curdy precipitate, info- 
luble in nitric acid. To enfure the operation of this 
teft, the alkaline and earthy carbonates muft be previoufly 
faturated with nitric acid ; and the fulphuric acid, if any be 
prefent, muft be feparated by the nitrate of barytes. Bo- 
racic acid is detefted by means of the acetate of lead. The 
precipitate formed is infoluWe in acetic acid. To render 
this teft certain, the alkalies and earths muft previoufly be 
faturated with acetic acid, and the fulphuric and muriatic 
acids removed by means of the acetate of ftrontian and the 
acetate of filver. 

Such is a brief account of the different tejls ufually em- 
ployed to deteft the ingredients prefent in mineral waters, 
and the moft obvious precautions to be obferved in their ufe. 
It is proper, however, to obferve, that there are many cir- 
cumftances to be attended to, in the ufe of tefts in general, 
which can only be learnt by perfonal obfervation and prac- 
tice, and that the inexperienced chemift is very hable to be 
mifled by them. 

d. Having thus acquired, by the employment of tefts, 
a general knowledge of the ingredients contained in a mineral 
water, the next objeft is to endeavour to afcertain the 
quantities and modes of combination in which they exift ; 
and this cwiftitutes by far the moft difiicult part of the 

There are two general modes of condufting the analyfis 
of a mineral water : one is to feparate, by various appro- 
priate nianipiUations, the different ingredients in the fame 
compound forms in which they are fuppofed to aftually exift 
in the water. The other, recommended particularly by 
Dr. Murray, is to afcertain, chiefly by means of tefts, the 
quantities of the different fimple fubftances, and afterwards 
to ejlimate from them the quantities of the compounds. 
The firll of thefe modes, and in fonie inftances a combina- 
tion of both, is the one which has hitherto been generally 
adopted by chemifts ; we fhall, therefore, give a fhort ac- 
count of the manipulations had recourfe to for feparating 
a few of the fubftances moft ufually occurring in miner^ 

I. The gafeous matters are firft to be feparated in the 
manner formerly mentioned, and their grofs amount afcer- 
tained by admeafurement in a jar graduated into cubic 
inches. Sulphuretted hydrogen, if it be prefent with other 
gafes, is firft to be feparated by immerfing the jar in warm 
water, and introducing nitric acid, which abforbs the ful- 
phuretted hydrogen, and the diminution of bulk denotes its 



quantity. If fulphurous acid be prefcnt, the above ftep is 
unneceflary, for fulpliurettcd hydrogen never exifts in water 
contaiuing this acid. Sulphurous acid may be feparated by 
introducing into the gafeous mixture a quantity of the 
peroxyd of lead, in a ilate of powder. This will gradually 
abforb the whole, and the diminution of bulk, as before, 
will denote its quantity. The introduftion of a little potafh, 
after this, will abforb the carbonic acid. The 
gafcs muft be oxygen and azote. The oxygen may be fe- 
parated by introducing a piece of phofphoruj, or by other 
well-known eudiometrical means ; and the azote will remain 
laft of all, unafFeAed by any of thefe proceffes. 

2. The earthy carbonates, if any be prefent, are firft to 
be feparatsd by boiling a given portion of the water for a 
quarter of an hour. The precipitate thus obtained may 
confift of a mixture of the carbonates of lime, of magnefia, 
of iron, and of alumina, and even of the fulphate of lime. 
Suppofing all thefe to be prefent, the precipitate is to be 
treated with dilute muriatic acid, which will diffolve the 
whole, except the alumina and fulphate of lime. Dry this 
refiduum in a red heat, and note the weight. Then boil it 
in a folution of carbonate of foda ; faturate the foda with 
muriatic acid, and boil the mixture for half an hour : car- 
bonates of lime and alumina will be precipitated ; the hme 
may be then difTolved by acetic acid, while the alumina will 
remain ; and thus the weight of each may be afcertained. 

The muriatic folution contains hme, magnefia, and iron. 
To feparate thefe, add ammonia, which will precipitate the 
iron and part of the magnefia. Dry the precipitate, and 
expofe it to the air for fome time in a temperature of about 
200*. The ms^-tfia may be then feparated by acetic acid, 
and the acetate thus formed is to be added to the muriatic 
folution. The iron is rio.v to be rediffolvcd in muriatic 
acid, precipitated by an alkaline carbonate, and dried and 

Muriate of lime and magnefia ftill remain in folution. 
To feparate them, add fulphuric acid as long as any pre- 
cipitate appears, then heat the folution, and concentrate. 
The fulphate of lime thus obtained is to be heated to red- 
nefs, and its weight afcertidned. Lallly, the magnefia 
may be feparated by an alkahne carbonate, or, what is 
much better, by the phofphate of ammonia. 

3. To afcertain the quantity of the alkaline carbonates, 
fuppofing them to exift in waters, determine how much of 
any dilute acid, whofe ttrcngth has been previoudy carefully 
afcertained, is neceflary to faturate them ; and from this the 
quantity of alkali can be readily ellimated. 

4. The alkaline and earthy fulphates may be eftimated by 
the following methods. 

The alkaline fulphates may be determined by precipi- 
tating their acid by means of the nitrate of barytes, having 
previouQy feparated all the earthy fulphates. 

Sulphate of lime is readily eftimated by evaporating the 
water to a few ounces, the earthy carbonates being pre- 
vioufly faturated with nitric acid, and precipitating the ful- 
phate of lime by means of dilute alcohol. 

If the fulphate of magnefia or alumina be the only ful- 
phate prefent, the quantity of either can be readily eftimated. 
If they exift together, the two earths may be precipitated 
by foda, and afterwards feparated by acetic acid in the 
manner above-mentioned. If fulphate of hme be alfo pre- 
fent, this may be previoufly feparated in a great degree, as 
above ; or, what is preferable, the lime may be precipitated 
by an alkali along with the other earths, and afterwards 
feparated. The fame holds good alfo with the fulphate of 
iron ; or the iron may be feparated by expofing the water 

for fome days to the air, and mixing with it a portion of 
alumina. The oxyd of iron and fulphate of alumina are 
precipitated together, and may be eafily feparated, and the 
quantity of iron afcertained. 

5. If muriate of potafti or foda exift alone in water, its 
quantity can be readily eftimated by precipitating the 
muriatic acid with the nitrait. of lilver. The fame procefs 
may be followed, if the alkahne carbonates be prefent ; 
only thefe carbonates mull be previoufly faturated with ful- 
phuric acid, and, inftead of ufing the nitrate, the fulphate 
of filver is to be employed. 

If the alkaline muriates exift along with more or lefs of 
the earthy muriates, or with the muriate of iron, wthout 
any other falls, the whole of the earths may be feparated 
by barytes water, and their quantities eftimated as before. 
To difcover the proportion of the alkaline muriates, the 
barytes is to be feparated by fulphuric acid, and the muriatic 
acid expelled by heat. The quantity of the alkaline mu- 
riates may be then afcertained by evaporation. 

When fulphates and muriates exift together, they may be 
feparated by evaporating the whole to drynefs, and diflblving 
the earthy muriates in alcohol ; or, when the water has 
been duly concentrated, by precipitating the fulphates with 
the fame fluid. 

When alkaline and earthy muriates exift with fulphate of 
lime, this laft fait is to be decompofed by means of the 
muriate of barytes. The eftimation is then to be condufted 
as if nothing but muriates are prefent, only the proportion 
of muriatic acid which united in the muriate of barytes, 
added, muft be allowed for. 

When muriates of foda, magnefia, and alumina, are pre- 
fent, together with fulphates of lime and magnefia, the water 
is better examined by two diftinA operations. To one por- 
tion add carbonate of magnefia, till the whole of the lime 
and alumina be precipitated. Afcertain the quantity of 
hme, which gives the proportion of fulphate of lime. Pre- 
cipitate tlie lulphuric acid by muriate of barytes : this gives 
the quantity contained in the fulphate of magnefia and ful- 
phate of hme ; and the quantity of fulphate of hme being 
previoufly known, that of the fulphate of magnefia can be 
eafily eftimated. To a fecond portion of the water add 
lime-water, till the whole of the magnefia and alumina be 
feparated. From the weight of thefe earths the quantity of 
their muriates may be eftimated, that portion of the mag- 
nefia previoufly found to be in union with fulphuric acid 
being dcduAed. After this, remove the fulphuric acid by 
barytes water, and the lime by carbonic acid, and the liquid 
evaporated to dryncfs will leave the common fait. 

6. Laftly : If the fixed mineral acids fliould alone be 
found to exift in a water, it need fcarcely be obfcrved that 
their quantities can be readily afcertained ; the fulphuric 
acid by means of a barytic fait, and tiie muriatic acid by 
means of a fait of filver. 

All thefe diflcrent precipitates fliould be dried uniformly, 
or at lead at fome known degree of temperature. It is not 
eafy to fix this point, which muft in a groat degree be regu- 
lated by the nature of the fait, and the peculiar views of the 
analyft ; fome choofiiig to reduce the falls to an anhydrous, 
others to a cryftalli/.cd ftate. As a fort of check alfo to 
the analyfis, it is proper to evaporate a known quantity of 
the water to drynefs, in order to learn the grofs amount of 
the faliiie matters it contains, which amount is to be com- 
pared with the refults as obtained by the different procefl'cs 
of the analyfis. 

Such are a few of the moft common methods recom- 
mended for feparating and afccrtaining the proportions of the 
10 different 


different faline fubftances contained in a mineral water. 
They muft of courfe be varied according to circumftances ; 
but this, as well as the application of other methods, muft: 
depend upon the praftical knowledge and judgment of the 

The principles, however, upon which many of the above 
analytical procefTes are founded, have been lately called in 
queftion by Dr. Murray of Edinburgh, and we think very 
juftly. That gentleman has endeavoured to (hew, that we 
by no means arrive atajuft knowledge of the conftituents of 
a mineral water by thefe procefles, and that many of the 
compounds obtained by them are determined by the pro- 
cefles themfelves. The following quotation, from a paper 
by Dr. Murray, entitled " A general Formula for the 
Analyfis of Mineral Waters," in the eighth volume of the 
Tranfaftions of the Royal Society of Edinburgh, will con- 
vey a diftinft idea of his opinions and mode of reafoning 
upon the fubjeft. 

Two methods of analyfis have been employed for dif- 
covering the compofition of mineral waters, wliat may be 
called the direft method,"in which, by evaporation, aided by 
the fubfequent application of folvents, or fometimes by 
precipitants, certain compound falts are obtained ; and what 
may be called the indired method, in which, by the ufe of 
reagents, the principles of thefe falts, and bafes of which 
they are formed, are difcovered, and their quantities efti- 
mated, whence the particular falts and their proportions 
may be inferred. 

Chemifts have always confidered the former of thefe me- 
thods as affording tlif moft certain and effential information. 
They have not neglefted the latter, but they have ufually 
employed it as fubordinate to the other. The falts pro- 
cured by evaporation have been uniformly confidered as the 
real ingredients ; and nothing more was required, therefore, 
it was imagined, for the accuracy of the analyfis, than the 
obtaining them pure, and eftimating their quantities with 
precifion. On the contrary, in obtaining the elements 
merely, no information, it was believed, was gained with 
regard to the real compofition ; for it ftill remained to be 
determined in what mode they were combined : and this, it 
was fuppofed, could be Inferred only from the compounds 
aftually obtained. This method, therefore, when employed 
with a view to eftimate quantities, has been had recourfe to 
only to obviate particular difficulties attending the execution 
of the other, or to give greater accuracy to the propor- 
tions, or, at furtheft, when the compofition is very fimple, 
confifting chiefly of one genus of falts. 

Another circumftance contributed to lead to a preference 
of the direft mode of analyfis, — the uncertainty attending 
the determination of the proportions of the elements of the 
compound falts. This uncertainty was fuch, that even 
from the moft exaft determination of the abfolute quantities 
of the acids and bafes exifting in a mineral water, it would 
have been difficult, or nearly imprafticable, to aflign the 
precife compofition and the real proportions of the com- 
pound falts : and hence the neceffity of employing the direft 
method of obtaining them. 

The prefent ftate of the fcience leads to other views. 

If the conclufion was juft, that the falts obtained by eva- 
poration, or any analogous procefs from a mineral water, 
are its real ingredients, no doubt could remain of the fu- 
periority of the direft method of analyfis, and even of the 
abfolute neceffity of employing it. But no illuftrations, I 
believe, are required to prove that this conclufion is not ne- 
cefTarily true. The concentration by the evaporation muft, in 
many cafes, change the ftate of combination ; and the falts 
obtained are hence frequently piodufts of the 6peration, not 


origfinal ingredients. Whether they are fo or not, and what 
the real compofition is, are to be determined on other 
grounds than ou their being aftually obtained ; and no more 
information is gained, therefore, with regard to that com- 
pofition, by their being procured, than by their elements 
being difcovered ; for when thefe are known, and their 
quantities are determined, we can, according to the prin- 
ciple from which the aftual modes of combination are in- 
ferred, whatever this may be, afTign with equal facility the 
quantities of the binary compounds they form. 

The accuracy with which the proportions of the confti- 
tuent principles of the greater number of the compound falts 
are now determined, enables us alfo to do this with as much 
precifion as by obtaining the compounds themfelves ; and if 
any error fhould exift in the eftimation of their proportions, 
the profecution of thefe refearches could not fail foon to 
difcover it. 

The mode of determining the compofition of a mineral 
water, by difcovering the acids and bafes which it contains, 
admits in general of greater facility of execution, and more 
accuracy, than the mode of determining by obtaining infu- 
lated the compound falts. Nothing is more difficult than to 
effeft the entire feparation of falts by cryftallization, aided 
even by the ufual methods of the aftion of alcohol, either as 
a folvent or a precipitant, or by the aftion of water as a 
folvent at different temperatures : in many cafes, it cannot 
be completely attained, and the analyfis muft be deficient in 
accuracy. No fuch difficulty is attached to the other me- 
thod. The principles being difcovered, and their quantities 
eftimated in general from their precipitation in infoluble 
compounds, their entire feparation is eafily effefted. No- 
thing is eafier, for example, than to eftimate the total 
quantity of fulphuric acid by precipitation by barytes, or 
of lime by precipitation with oxalic acid ; and this method 
has one peculiar advantage with regard to accuracy, that if 
any error is committed in the eftimation of any of the prin- 
ciples, it is difcovered in the fubfequent ttep of inferring the 
binary combinations : fince, if all the elements do not bear 
that due proportion to each other, which is neceffary to 
produce the ftate of neutralization, the excefs or deficiency 
becomes apparent, and of courfe the error is detefted. 
The indireft method, then, has every advantage over the 
other, both in accuracy and facility of execution. 

Another advantage is derived from thefe views, if they 
are juft, that of precluding the difcuffion of queftions, 
which otherwife fall to be confidered, and which muft often 
be of difficult determination, if they .;re even capable of 
being determined. From the ftate of combination being 
liable to be influenced by evaporation, or any other analytic 
operation, by which the falts exifting in a mineral water are 
attempted to be procured, difcordant refults will often be 
obtained, according to the methods employed : the propor- 
tions at leaft will be different, and fometimes even produfts 
will be found by one method, which are not by another. 
In a water which is of a complicated compofition, this will 
more peculiarly be the cafe. The Cheltenham waters, for 
example, have in different analyfes afforded refults confider- 
ably different : and on the fuppofition of the falts procured 
being the real ingredients, this diverfity muft be afcribed to 
inaccuracy ; and ample room for difcuffion with regard to 
this is introduced. In like manner, it has often been a fub- 
jeft of controverfy whether lea-water contains fulphate of 
foda with fulphate of magnefia. All fuch difcuffions, how- 
ever, are fuperfluous. The falts procured are not necef- 
farily the real ingredients, but in part, at leaft, are produfts 
of the operation ; liable, therefore, to be obtained or not, 
or to be obtained in different proportions, according to the 
D method 


method employed : and all that can be done witlj precifion 
is to eftimate the elements, and then to exhibit their binary 
combinations, according to whatever may be the moll pro- 
bable view of the real compofition. 

The method propofed by Mr. Kirwan, formerly al- 
luded to, confifts in determining, chiefly by tefts, the 
quantity of the different faline fubllances prefent. But the 
complicated nature of many of the formulae, befide the very 
principle of the method itfelf, being Uable to moft of the 
objeAions above urged by Dr. Murray againft that in com- 
mon ufe, render its application difficult, and refults uncer- 
tain. Upon the whole, therefore, we have no hefitation in 
faying, that we confider Dr. Murray's views and methods 
as by far the bed, and moft likely to lead to correa con- 
dufions, that have yet appeared, and which may be ftatcd 
in few words, as follows : 

" Determine by precipitants the vveiglit of the acids and 
bafes prefent in a mineral water. Suppofe them united m 
fuch a manner that they (liall form the moft foluble falls : 
thefe falts will conftitute the true fabne conttituents of the 
water under examination." 

Dr. Murray illuftrates his method of procedure by fup- 
pofing, as an example, a water found, by the ufual tefts, 
to contain the carbonates, fulphates, and muriates of lime, 
magnefia, and foda. The water is to be reduced by eva- 
poration as far as can be done, without occafioning any 
fenfible precipitation or cryftallization. A faturated folu- 
tion of muriate of barytcs is then direfted to be added as 
long as any precipitate falls, and no longer. This precipi- 
tates the whole of the fulphuric and carbonic acids, and the 
carbonate of barytes is to be feparated from the fulphate by 
diluted muriatic acid. Add to the refidual liquor a folution 
of oxalate of ammonia as long as any turbid appearance is 
produced. By this the whole of the lime is feparated. 
The oxalate of lime is to be calcined, and converted into 
fulphate of lime, from which the quantity of pure lime may 
be readily eftimatcd. The next ftep is to precipitate the 
magnefia ; and for this piirpofe, Dr. Murray recommends a 
modification of Dr. Wollafton's procefs. This confifts in 
adding, firft, a folution of neutral carbonate of ammonia, 
and afterwards a ftrong folution of phofphoric acid, or 
phofphate of ammonia ; taking care to leave an excefs of 
the carbonate of ammonia. By thefe procefles, the whole 
of the magnefia is obtained in the ftate of triple phofphate, 
and its quantity can be readily eftimated. Muriate of foda 
now remains in folution, and its quantity can be obtained by 
CTaporation. As a check, however, to the different pro- 
cefles, it may be proper to afcertain the quantity of muriatic 
acid prefent by means of the nitrate of filver. 

If alumina, filica, or iron be prefent, they are beft fepa- 
rated by diftinft proceffes, in the manner formerly de- 

Laftly, Dr. Murray recommends that the refults of an 
analyfis be ftated in three modes : ift. The quantities of the 
acids and bafes ; 2dly, The quantities of the binary com- 
pounds, as inferred from the principle that the moll foluble 
compounds are the ingredients ; and 3dly, The quantities 
of the binary compounds, fuch as they are obtained by 
the ufual modes of analyfis. The refults will be thus pre- 
fented in every point of view. As an inftance of this 
method of ftating the refults of an analyfis, we refer our 
readers to what we have faid on fea-wattr in the prefent 

Mineral IVaters, artificial Preparation o/— Chemiftry had 
no fooner developed the compofition of mineral waters, than 
it fiiggefted methods of preparing them artificially. Ac- 
cordingly, Bergman and others have given many formulae for 

this purpofe, fome of which approach the truth, while 
others arc very imperfetl. When the compofition of a 
water is very fimple, nothing more is required to form it 
artifici.iUy than to know the nature and quantity of the 
faline fubftances prefent, and to diffolve fimilar quantities of 
the fame faline fubftances in the fame proportion of water. 
In the earlier periods of chemical inveftigalion, before the 
nature of gafeous fubftances was underftood, no attempts 
of courfe could be made to imitate the important clafs of 
waters which derive their chief properties from the prefence 
of fuch fubllances ; but chemifts no fooner became ac- 
quainted with the nature of gafcs, than they began to devife 
methods of imitating thefe alfo ; and artificial carbonated 
waters have been long fince prepared as an article of com- 
merce, under the name oifoda tvater, fuperior in point of im- 
pregnation to any acidulous waters known. See Pvrmont. 

It is true that there are fome inftances of natural chemical 
folution, which art has not even yet been able to imitate. 
Of this kind is the folution of filcx, which occafionally oc- 
curs in mineral waters. It is doubtful, however, if this 
earth is capable of exerting any falutary effects on tlie animal 
economy ; and, therefore, we have little occafion perhaps 
to regret our inability to effect its folution. Another defeft 
in the formation of artificial mineral waters is, that many of 
the more important ones cannot be obtained in large quan- 
tities for bathing, &c. without fo great a degree of cxpence 
and trouble, as to entirely preclude their ufe. 

On the other hand it feems plaufible, in tiieory at leall, 
that we can improve upon the compofition of many mineral 
waters. Thus, many mineral waters contain ingredients, 
which, either from the minutenefs of the proportion in which 
they exift, or from their inert nature, may be deemed as 
fuperfluous, or in fome inftances as injurious. Again, 
others contain their aftive ingredient in fuch fmall quantities, 
as to require an inconvenient bulk of the water to produce 
the defired effeft : all which defefts may be remedied in the 
artificial preparation, by leaving out the ufelefs or noxious 
matter, and increafing that in which the proper medicinal 
virtue refides. Bcfides thefe advantages alfo, we have it in 
our power to form new and valuable compounds, which are 
no where to be met with in a natural ftate. 

The firft ftep to the artificial formation of a mineral 
water is, of courfe, to know the exadt compofition of the 
water we would imitate. Many of the ingredients, how- 
ever, obtained from mineral waters by the ufual modes of 
analyfis, are very little foluble in water : fuch, for example, 
are the fulphate and carbonate of lime, &c. which we (hould 
attempt in vain to diffolve directly in water. Other modes, 
therefore, muft be devifed for this purpofe ; and Dr. Mur- 
ray's views of the compofition of mineral waters in general 
will enable us to effeft our objedt, in moft inftances, very 
readily and completely, as the following example will 

Suppofe we wiftied to imitate the Seltzer water, an 
Englifh pint of which, according to Bergman's analyfis, 
contains, as before mentioned, of 

till). Inches. 

Carbonic acid - - - - 17 

Carbonate of lime 
Carbonate of magnefia 
Carbonate of foda 
Muriate of foda 






Of thefe ingredients, neither the carbonate of lime nor 
tnagnefia are foluble in water, nor can be rendered fo, with- 
out a tedious procefs of impregnating the water, through 
which they are diffufed, with carbonic acid gas. But if we 
adopt Dr. Murray's views, and confider a pint of this water 
as aAually containing of 

Cub. Inches. 
Carbonic acid gas 17 

Muriate of lime 
Muriate of magnefia 
Muriate of foda 
Carbonate of foda 




10.3 dry, or 1 8 cryftallized. 


■we can eafily imitate its compofition in the following 
manner : 

About 35 grains of muriatic acid, of the ftrength ufually 
met with in the (hops, are to be put into a ftrong bottle, 
with a pint of water, the acid being introduced to the bot- 
tom of the water by a long funnel. Three grains of pure 
white marble in coarfe powder are then to be dropped in, 
and the bottle clofed. When thefe are didolved, five grains 
of the common carbonate of magnefia in powder are to be 
added ; and after the folution of this, 32 grains of cryftal- 
lired carbonate of foda, or what is equivalent to this, and 
preferable, as affording more carbonic acid, 27 grains of 
bicarbonate of foda, are to be put in. The bottle is to be 
clofed accurately, (haken, and inverted. In a fhort time 
a perfeft folution takes place, and a liquor is obtained 
tranfparent, which fparkles when poured out, has a plea- 
fant tafte, and in its compofition refembles the Seltzer 

it might be fuppofed, fays Dr. Murray, that fo large a 
proportion of carbonate of foda could not exift with the 
muriates of magnefia and lime, without decompofing them ; 
but on making the experiment, it was found that the above 
qnantities might be diflblved in a pint of water, indepen- 
dently of the excefs of carbonic acid, without any apparent 
decompofition ; the folution remaining tranfparent, even on 
expofure to the air. 

Upon fimilar principles may the compofition of almoft 
every other mineral water be readily imitated. 

We have an agreeable imitation of acidulous waters, under 
the term of what is called the effervefdng draught. This 
confifts of two folutions, one of an alkaline carbonate, and 
the other of the citric or fome other vegetable acid, which 
are direfted to be mixed together, and fwallowed during 
the aft of effervefcence. A more portable form of this 
grateful draught is to be obtained in the (hops, under the 
name of Sodaic poivders, Seidlet% powders, Sec. in which 
the requifite proportions of alkali and acid in their dry ftate 
are formed into feparate httle packets, one of each of which 
•is direfted to be didolved feparately in water, and the two 
folutions to be then mixed, and fwallowed during the aft of 
efferrefcence, as before. 

The following, therefore, may be laid down as a general 
rule for the artificial preparation of mineral waters : — Afcer- 
tain, upon Dr. Murray's principles, the precife propor- 
tions of the mo/l foluble falts that can be prefent in any 
given water ; diiTolve fimilar proportions of the fame falts 
in an equal quantity of water, and a compound water will 
be obtained, precilely fimilar in its compofition to the 

Catalogue of the mofl important mineral Waters 1"he fol- 
lowing catalogue is intended to comprife the principal 
mineral waters of Great Britain, and fome of the more im- 
portant ones of other countries. Our readers will recoUeft 
that, in the preceding article, we divided natural waters 
into potable, faline, chalybeate, acidulous, fulphureous, and 
thermal, and defcribed the general chemical and medicinal 
properties of each clafs, as well as of their compounds. 
To prevent repetition, and to fave room, therefore, we have 
attempted to refer the diff"erent fprings, mentioned in the 
following catalogue, to one or other of the above clafles : 
thus, when a fpring is ftatcd to be faline, its general com- 
pofition and properties are to be underftood to refemble the 
clafs of faline waters ; and fo of the reft. 

The moderns have very properly exploded the old notion 
of the myilerious ^n^fpecific operation of particular fprings. 
But even if this cogent reafon for generalization did not 
exift, it would be impoflible, in a work of the prefent defcrip- 
tion, to defcend to all the minuti^ of analyfis, &c. fuppofing 
them to be known, which is far from being the cafe: we 
have thouglit proper, however, to give a few of the more 
interefting and inftruftive recent analyfes of fome of the 
moft important fprings. 

Thofe fprings marked thus *, in the following lift, are 
more particularly defcribed in the preceding article, ae 
examples of the different clafles. 

Abcoxtrt. An aaidulous chalybeate fpring. See Ab- 


Aberbrothich, or Arbroath. An acidulous chalybeate 
fpring. See Aberbrothick. 

Adon. A faline fpring. See AcTON, 

Aghaloo, Tyrone, Ireland. A fulphureous fpring flightly 

* Aix-la-Chapelle. Sulphureous thermal fprings. See 


Alford. A faline fpring. See Alford. 

Alkerton, near Gloucefter. A faline fpring. 

Anaduff, Leitrira. A weak fulphureous fpring flightly 

Afhwood, Fermanagh. A fulphureous fpring flightly 

AJheron, Yorkfliire. A ftrong fulphureous fpring 
flightly faline. 

Aflrope, Oxfordfhire. An acidulous chalybeate fpring. 

Afivarby, Lincolnftiire. A faline chalybeate fpring. 

Athlone, Weftmeath. A chalybeate fpring flightly 

d'Ax-enfoix, France. Sulphureous thermal fprings, in 
repute as baths. 

Baden. Sulphureous fprings, formerly in much repute as 
baths. See Baden. 

Bagnigge-Wells. Two fprings, one faline, the other 
chalybeate. See Paxcras. 

Baiit. Thermal fprings, in much repute among the Ro- 
mans. See Bai;e. 

Balaruc. Saline thermal fprings. See Balaruc. 

Ballycaflle. Two chalybeate fprings, one in which the 
iron is in combination with carbonic acid, the other with 
fulphuric acid. See Ballycastle. 

Ballynahinch, Downfliire. A fulphureous fpring, faid to 
contain iron. 

Bagneres, France. Thermal fprings, in much repute as 
baths. See Bagneres. 

Balflon, North America. A highly acidulous chalybeate 
fpring. According to the recent analyfis of a French 
cheraift, zj fluid ounces contain of 

D 2 Carbooic 


Carbonic acid 

Muriate of foda 
Carbonate of lime 
Muriate of magnefia 
Muriate of lime 
Carbonate of iron 

Cub. luchcj. 








is about 74°. A wine pint, 
analyfis, contains of 

Carbonic acid gas 
Common air 

Bartge. Sulphureous thermal fprings, in confiderable 
repute. See Barege. 

Bamet, Hertfordlhire. A weak faline fpring. At 
North-hall, about three miles from Barnet, is another of 
ihe fame dcfcription, but a little ftroiiger. 

Bath. Celebrated faline thermal fprings, containmg like- 
wife a little iron. (See Bath.) One of the moft recent 
and probably correft analyfes of thefe waters is by Mr. 
Phillips. According to this gentleman, a wine pint con- 
tains of „ , , ■ 

Cub. Inches. 

Carbonic acid - - - !■* 

Sulphate of lime 

Muriate of foda 

Sulphate of foda 

Carbonate of lime 


Oxyd of iron 







Bilkin, Yorkfhire. A weak faline fulphureous fpring. 
Binley, Warwickfhire. A faline chalybeate fpring. 
Borroiudak, Cumberland. A ftrong faline water. See 


Borfct. Sulphureous thermal fprings, in confiderable 
repute. See BoRSET. 

Brabach, Germany. An acidulous chalybeate fpring. 

Brandola, Italy. A weak acidulous chalybeate fpring. 

Brentwood, Effex. A faline fpring. 

Brighton. A chalybeate fpring : fulphate of iron. (See 
Brighthelmston.) According to Dr. Marcet's analyfis, 
a wine pint contains of 

Carbonic acid gas 

Sulphate of iron 
Sulphate of lime 
Muriate of foda 
Muriate of magnefia 

Cub. Inches. 





BiiJlol Hofwelh. A fimple thermal water. As this 
Ipring has not been dcfcribed in its proper place, we fhall 
infert the following (hort account of it here. This water is 
inodorous, perfeftly limpid and fparkhng, and fends forth 
air-bubblc8 when poured into a glafs. It is agreeable to 
the palate, but has no decided taile. Its fpccific gravity is 
ftaled to be 1.00077. Its temperature, upon an average, 

according to Dr. Carrick's 

Cub. Inches. 


Muriate of magnefia 
Muriate of foda 
Sulphate of foda 
Sulphate of lime 
Carbonate of lime 









It was formerly much celebrated in confumption, but its 
fuppofed good effefts in this difeafe have been juftly called 
in queftion by modern writers. 

Bromley, Kent. A chalybeate fpring. See Bromlev. 
Broughton, Yorkfhire. A ftrong faline fulphureous 
fpring, iimilar to that of Harrowgate. 

Buch, near Carlfbad, in Bohemia. A weak acidulous 

Buglawton, Chefliire. A fahne fulphureous water. 

Burlington, or Bridlington, Yorkftlire. A chalybeate water 
(lightly faline. 

Burnley, Lancaftiire. A chalybeate water flightly faline. 

*Buxton. A fimple thermal water. See Buxton-^j/w. 

Cannock, Staffordfliire. A chalybeate water. 

Cargyrle, near Chefter. A weak faline water. 

Carljbad. Celebrated acidulo-chalybeate thermal fpfings. 
See Carlsbad. 

Carlton, Nottingham. A chalybeate water. 

Cajlleconnel. A chalybeate water. See Castleconnel. 

Cq/llemain. A fulphureous fpring faid to contain iron. 
See Castlemain. 

Cawley, Derbyfhire. A fulphureous water flightly faline. 

Canuthorp, Lincolnfhire. A chalybeate fpring flightly 

Chedlington, Oxfordfhire. A fulphureous water flightly 

Chaudt Fontaine, near Liege, Germany. Thermal fprings 
celebrated as baths. 

*Cheltenham. Saline and faline chalybeate fprings. See 

Chippenham, Wiltfliire. A chalybeate fpring. 

Cleves. An acidulous chalybeate fpring. See Cleves. 

Clifton, Oxfordfhire. A faline fpring. 

Cobham, Surry. A chalybeate water. 

Codfal Wood, Staffordlhire. A fulphureous fpring. 

Colchefter, Eflcx. A faline fpring. 

Colurian, Cornwall. A chalybeate fpring. 

Comner, or Cumner, Berklhire. A weak faline fpring. 

Corjlorphine, near Edinburgh. A weak fulphureous fpnng 
flightly faline. 

Coventry. A fahne ch.ilybeate fpring. See Coventry. 

Cricile Spa, Lancafhire. A ftrong fahne fulphureous water. 

Croft, Yorkftlire. A fulphureous water (lightly faline. 

Crofs town, Waterford. A fulphureous fpring. 

Cunley-houfe, Lancaftiire. A ftrong fulphureous fpring 
flightly faline. 

Deddington. Saline fulphureous fprings. Sec Ded- 


Derby. A chalybeate fpring. 



Derr'mdaff, Cavan. A fulphureoas fpring flightly faline. 

Derry-btnch, Fermanagh. A fulphureous fpring. 

Dog and Duel, St. George's Fields, Southwark. A faline 

Drig-ivell, Cumberland. An acidulous chalybeate fpring. 

Dnmafnave, Leitrira. A ftrong fulphureous fpring flightly 

Dublin. Several weak faline fprings. 

Dulivich, Kent. Pretty ftrong faline fpring. 

Dunblane, Perthfhire. Thefe fprings have been only lately 
difcovered. They have been accurately analyfedby Dr. Mur- 
ray. There are two fprings, both of a fimilar nature, that is 
to fay, faline, with a minute proportion of iron. A wine 
pint of the north fpring was found by Dr. M. to contain of 

Muriate of foda ... 

Muriate of lime ... 

Sulphate of hme . . - 

Carbonate of lime with a trace of iron 

- 24-3 

- i8. 

- 3-1 

- 0.5 

The fame quantity of the /out h Jpring yielded 

Muriate of foda .... 

Muriate of lime . . . . 

Sulphate of lime . . . - 

Carbonate of lime .... 

Oxyd of iron .... 





Dun/e, Scotland. A chalybeate fpring. 

Durham. A ftrong fulphureous water flightly faline. 

Egra, Bohemia. A celebrated faline chalybeate fpring. 
See Egka. 

Epfom, A celebrated faline fpring. See Epsom. 

Feljiead, Effex. A chalybeate fpring. 

Filah, Yorkfliire. A faline chalybeate fpring. 

Francfort on the Maine. Saline fulphureous fprings. 
See Francfort. 

Galiuay, Ireland. A chalybeate fpring. 

Geyfer, Iceland. Remarkable thermal fprings. See 

Glanmile, Ireland. A chalybeate fpring. 

Glajlonbury. A chalybeate fpring flightly faline^ See 

Glendy, Angusftiire. A ftrong chalybeate fpring. 

Gran/haw, Downfliire. A chalybeate fpring. 

Haigh, Lancafliire. A chalybeate fprmg ; fulphate of iron. 

Hampjlead. A chalybeate water. See Hampstead. The 
moft recent analyfis of this water is by Mr. Blifs, according 
to whom a wine gallon contains of 

Cub. Inches. 

Carbonic acid - - - - lo.i 

Atmofpheric air - - - - 90.9 

Oxyd of iron 
Muriate of magnefia 
Sulphate of lime - 
Muriate of foda nearly 
Of fUex about 




Uanbridge, Lancaftiire. A chalybeate water (lightly 

Hanlys, Shropftiire. Two fprings, one faline the other 

*Harro'wgate. Saline fulphureous fprings. See Har- 


Hartfell, Annandale. A chalybeate fpring: fulphate of 
iron. According to Dr. Garnett's analyfis, a wine pint of 
this water contains of 

Sulphate of iron ... 10.5 

Sulphate of alumina - - - i.c 

Oxyd of iron .... 1.875 


Hartlepool. A chalybeate fpring. See Hartlepool. 

Holt, Wiltfliire. A weak faline water. 

Holt-nevtl, Leicefterfhire. A chalybeate fpring : fulphate 
of iron. See Holt Waters. 

Jejfop's Well, near Cobham, Surry. A ftrong faline 
water flightly chalybeate. 

Ilmington, Warwickfliire. A chalybeate fpring. 

Ingleivhite, Lancaftiire. A ftrong chalybeate fpring. 

IJle of Wight. A very ftrong chalybeate : fulphate of 

Iflington. A chalybeate fpring. See Islington. 

Kanturk, Cork. A chalybeate fpring. 

Kaitrine Loch, Scotland. On the north fide of this 
lake is a ftrong chalybeate fpring. 

Keddleflone, Derbyfliire. A Itrong fulphureous water 
moderately faline. 

Kenfington. A faline fpring. See KENSINGTON. 

Kilbreiv, Meath. A chalybeate water ; fulphate of iron. 

Kilburn, Middlefex. A fahne fpring. 

Kilroot, Antrim. A faline fpring. 

Kiling-Jhanvally, Fermanagh. A chalybeate water flightly 

Killqfher, Fermanagh. A ftrong fulphureous water. 

Kinalton, or Kynolten, Nottinghamfliire. A weak faline 

Kincardine. A chalybeate fpring. 

King's-cliff, Northamptonfliire. A chalybeate fpring 
weakly faline. 

Kirby or Kirkhy-thower, Weftmoreland. Two chaly- 
beate fprings. 

Knarejborough, the Dropping-tuell, contains lime held in 
folution by carbonic acid. See Knakesborough. 

Knowfley, Lancaftiire. A chalybeate fpring. 

Korytna, Moravia. A very ftrong fulphureous fpring, 

Kuka, Bohemia. A chalybeate acidulous water. 

Lancafler. A chalybeate fpring flightly faline. 

Latham, Lancaftiire. A chalybeate fpring. 

Leuk, Valois, Switzerland. Thermal fprings. 

Llandrindod, Radnorfliire. Three fprings; one faline, 
another fulphureous, and the third chalybeate. 

Llangybi, Carnarvonftiire. A fahne fpring. 

Leamington. A faline fpring. See Warwick. 

Leez, EfTex. A chalybeate fpring. 

Lincomb, Bath. A chalybeate fprmg flightly faline. 

Li/beak, Fermanagh. Two fulphureous fprings. 

Lis-done-varna, Clare. A ftrong chalybeate water. 

Loanjbury, Yorkfliire. A fulphureous fpring flightly 

Maccroom, near Cork. A chalybeate fpring. 

Mahereberg, Kerry . A faline fpring. 



Malkiv, Cork. A pure thermal fpring. See Mallow. 

Mailo-h Yorkftiire. A ftrong chalybeate fpring mode- 
rately faliiic. 

•Malvrm, Worcefter(hire. Very pure fprings. See 
Malvern. One wine gallon of the Malvern Holywell 
waters, according to Dr. Wilfon, contains of 


Carbonate of foda - - - 5-33 

Carbonate of lime - - - 1.6 

Carbonate of magnefia . - - .919 

Carbonate of iron - - - -6^5 

Sulphate of foda - - - 2-896 

Muriate of foda - - - '-553 

Refiduum, filex - - - 1-687 


According to the fame chemift, one gallon of the Malvern 
St. Ann's well contains of 


Carbonate of foda 
Carbonate of lime 
Carbonate of magnefia 
Carbonate of iron 
Sulphate of foda 
Muriate of foda 
Refiduum, files 




Marl/ball, Effex. A chalybeate water. 

Mattock, Derbylhire. Thermal fprings, temp, about 66°. 
See Matlock. 

Maudjley, Lancaftiire. A fulphureous water moderately 

Mechan, Fermanagh. Two fulphureous fprings. 

Millar^ J Spa. A chalybeate fpring. 

*Moffat, Annandale. Two fulphureous fprings. See 

Mofshoufe, Lancaftiire. A chalybeate fpring. 

Morcton, Shropftiire. A faline fpring. 

Mont ifOr, near Clermont, France. Sulphureous ther- 
mal fprings. 

Mount Pallas, Cavan. A chalybeate fpring. 

Mevil Holt. See Holt. 

Nczvnham Regis, Warwickfhire. Three chalybeate fprings 
(lightly fahne. 

Nfwton Dak, Yorkfliire. An acidulous water holding 
lime in folution. 

Ne'.vtan Ste-wart, Tyrone. A chalybeate fpring. 

Netdtn'ue, Germany. An acidulous water. 

Nohhcr, Meath. A chalybeate fpring : fulphatc of iron. 

Normanby, Yorkftiire. A fulphureous fpring flightly 

Nottington, Dorfetfhire. A ftrong fulphureous water. 

OrJIon, Nottingham. A chalybeate fpring. 

Oullon, Norfolk. A weak chalybeate fpnng. 

Oiuen Breun, Cavan. A fulphureous fpring (lightly faline. 

Pancrat, Middlefex. A faline fpring. 

Pajy, near Paris. A moderately ftrong chalybeate 

Pderhrad, Aberdeenftiire. A ftrong chalybeate fpnng. 
See Peterhead. 

Peltygoe, Donegal. A ftrong fulphureous water, faline. 

Pucaithly, Perthftiire. Thcfc fprings refemble clofely 
thofe of Dunblane, and have been lately analyfed by Dr. 
Murray, according to whom a wine pint contains of 

Atmofpheric air 
Carbonic acid gas 

Muriate of foda 
Muriate of lime 
Sulphate of lime 
Carbonate of lime 

Cubic Inchrh 
- 0.5 





Plombiers, France. A thermal fpring. 
Pontgibault, France. A weak acidulous fpring. 
Pyrmont, Weftphalia. A highly acidulous chalybeate 
fpring. See Pvrmont. 

Queen's Camel, Somerfetftiire. A fulphureous fpring. 
Richmond, Surry. A faline fpring. 
Road, Wiltftiire. A chalybeate fpring. 
Rougham, Lancaftiire. A faline fpring. 
St. Bartholomew's Well, Cork. A chalybeate water 
flightly faline. 

St. Bernard's Well, Edinburgh. A fulphureous water 
fliglitly faline. 

St. Erafmus's Well, StafFordftiire. A weak faline water. 
St. Winifrid's Well, Flint. A very pure fpring. See 

Scarborough, Yorkftiire. A faline chalybeate fpring. See 

Schooley's Mountain, United States. A weak chalybeate 

Scollienfes, Switzerland. An acidulous chalybeate fpring. 
* Sea-water. See Sea and the former part of tliis article. 
*Sedlitz. A faline water. See Sedlitz. 
*Seltzer. An highly acidulous water. See Seltzer. 
Sene, or Seend, Wiltftiire. Two chalybeate fprings. 
*.S^(^Au/!i, near Sedhtz. A faline water. See Sedlitz. 
Shad'well. A faline chalybeate fpring : fnlphate of iron ? 
Shapmoor, Weftmoreland. A fulphureous fpring flightly 

Shetllewood, Derbyftiire, A fulphureous fpring flightly 

Shipton, Yorkftiire. A fulphureous fpring moderately 

Somerjham, Huntingdonftiirc. A chalybeate fpring : ful- 
phateof iron. See So.mersham. 

*Spa. Highly acidulous chalybeate fprings. See Spa. 
Stanger, Cumberland. A faline chalybeate fpring. 
Stenjield, Lincolnfliire. A chalybeate fpring flightly 

Streatham, Surry. A faline fpring. See Streatham. 
Suchaloza, Germany. An acidulous fpring. 
Sutton Bog, Oxfordftiire. A ilrong fulphureous fpring 
flightly faline. 

S-wadlingbar, Cavan. A fulphureous fpring. 
S-wanfea, Glamorganftiire. A chalybeate fpring: ful- 
phateofiron. See Swansea. 

Sydenham, Kent. A weak faline fpring. 
Tarkton, Lancaftiire. A chalybeate fpnng flightly faline. 
Tcwhjbury, Gloucefterftiire. A faline fpring. 
Thctford, Norfolk. A chalybeate fpring flightly aci- 

Thoroton, Nottinghamftiire. A chalybeate fpring flightly 

Thurjk, Yorkftiire. A faline chalybeate fpring. 



T/i/if//, Derbyfliire. A chalybeate fpring (lightly aci- 

Tilbury, Eflex. A faline fpring (lightly chalybeate. 

Toberbony, near Dublin. A faline fpring. 

Tonjlcm, Germany. A faline acidulous fpring in con- 
fiderable repute. 

Tralee, Kerry. A chalybeate fpring. 

*Tunbrlclge [Veils, Kent. A chalybeate fpring. See 
TUNBRIDGE [l^el/s. 

Upminjlcr, ElFex. A ftrong faline fulphureous fpring. 

Vahls, France. A weak acidulous fpring (lightly faline. 

Vichy, France. A highly acidulo-chalybeate thermal 
fpring. See Vichy. 

Wardrew, Northumberland. A faline fulphureous fpring. 

Warmbrunn, Silefia. Thermal fprings. 

Weather/lack, Weftmoreland. A faline chalybeate fpring. 

/fifZ/^nirow, Northampton (hire. A weak chalybeate fpring. 

Wejl AJhton, Wiltlhire. A weak chalybeate fpring. 

Wejlivood, Derby(hire. A chalybeate fpring : fulphate of 

Wexford, Ireland. A weak chalybeate fpring. 

Wh'tH -ilrrc, Lanca(hire. A chalybeate fpring. 

IVigan, Lancafhire. A chalybeate fpring. 

IVigglefworth, Yorklhire. A fulphureous fpring (lightly 

IVildungan, Germany. A weak acidulous water. 

IVitham, ElTex. A chalybeate fpring. 

iVirkf'Worth, Derbyfhire. A faline fulphureous fpring. 

Zahorovice, Germany. A weak faline acidulous water. 

*Zealand, New. An acidulous water : muriatic acid. 

See the article AtiUiE, where many thermal and other 
fprings are noticed, which have been omitted in the above 

Among the older writers on mineral waters, fee Rutty, 
Monro, EUiot, and others. One of the befl modern treatifes 
on mineral waters is doubtlefs that of Dr. Saunders, to 
which we have been particularly indebted. Detached clFays 
on particular waters are too numerous to be all noticed. 
Among the more recent publi(hed in this country may be 
enumerated thofe of Phillips on tlie Bath waters ; Scudamore 
on the Tunbridge Wells water ; Jones on the Spa waters ; 
and Brande on the Cheltenham waters. 

The chief of the older writers on the analyfis of mineral 
writers, are Bergman and Kirvvan. Latterly, fome very 
valuable effays have been pubhlhed on this fubjeA by 
Dr. Murray of Edinburgh, of which we have availed our- 
felves in the above article. 

Water of Cryjlallization, in Chemijlry, is a denomination 
applied to the water attrafted by many fahne bodies during 
the aft of cryftalhzation. Some falts contain no water of 
crydaUization, while others contain a very large proportion. 
Water always appears to enter into the compofition of 
cryftals in a definite proportion. Water can be commonly 
feparated from falts without afFefting their faline properties , 
and may be reftored to them by diffolving them in water, and 
fuffering them to cryftallize. See Crystallization and 

Waters, T)ijltlled or Simple, in Medicine and Pharmacy, 
confift chiefly of fimple water (lightly impregnated with the 
elTential oils of different plants, and are principally ufed as 
vehicles for more aflive remedies. They were formerly very 
numerous, but their numbers have been very properly much 
reduced by the moderns. See Aqu.'E Dtjlillate, where all 
thofe in common ufe are enumerated. 

W Ai'ER, Spirituous, Cordial, or Compound,\n Pharmacf,&ic. 
was the name formerly given to what are now denommated 
fpirits, the menftruum being alcohol, and the impregnating 

ingredients commonly various. See Aqu^ Cardiacs, and 
Spirit. For the methods of preparing fuch compounds, 
fee alfo Distillation, and Oil, ejfential. 

Water, in Agriculture and Rural Economy, is a fluid of 
great utihty for many different purpofes. The nature of the 
compofition of water, and the great power and capacity 
which it pofTefles of taking up and holding a variety of dif- 
ferent matters in the (late of diffufion or folution, as well as 
the circumftance of its being every where prefent amonglt 
almoft all kinds of bodies, renders it particularly ufeful in 
the growth of plants as crops, and in many other ways. 
Dr. Woodward, indeed, from finding it to contain the par- 
ticles of moll forts of extraneous fubllances, was led to 
fuppofe that fome of them were the proper matter of nutri- 
tion ; as water is conflantly found to afford fo much the lefs 
nourifhment, the more it is purified by dillillation, or other 
means. So that water, as fuch merely, did not appear to 
be the proper nutriment of vegetables, but only the medium 
or vehicle that contains the nutritious particles or properties, 
and which conveys them along with it through all the parts 
of the plant. The more full and complete knowledge of 
the nature and properties of water which has fince been ac- 
quired, have, however, fet the matter in a more clear and 
fatisfa(Slory point of view. See the article Water. 

Water is feldom, if ever, met with in a (late of perfeft 
purity, nor often in that even which is fufBciently fo for the 
different operations and ufes to which it may be necelfary to 
apply it. Nor have all the trials that have ever been made 
been yet capable of producing it perhaps perfedlly pure. 
There feems indeed to be no fort of (landard by which the 
weight and purity of water can be readily and eafily afcer- 
tained. It is, in fad, a very difficult matter, however ufe- 
ful and advantageous it might be in many different inten- 
tions, as water fcarcely ever continues for any length of 
time exaftly of the fame weight, or perhaps purity ; as by 
reSfon of the air and caloric, or matter of heat contained in 
it, much variation in refpeft to the former continually takes 
place. The effefts which different degrees of heat have on 
the gravity of water are well (liewn by the expanfion of it 
in boiling. It is this which makes the chief difficulty in 
fixing the fpecific gravity of water, in the view of fettling 
its degree of purity. The purefl water that is capable of 
being obtained is, however, thought by fome, as Mr. 
Hawkfbee, who has made many experiments on the fubjeft, 
to be eight hundred and fifty times heavier than air. But 
others, whofe trials have not been lefs numerous or correft, 
have made it not more than about eight hundred, or eight 
hundred and thirty-lix times heavier than air. From whence 
this general proportion may perhaps be deduced, which may 
be confidered as a fort of (landard in the bufinefs, that when 
the barometer is at 30°, and the thermometer at 55°, then 
water is eight hundred and twenty times heavier than air ; 
and that in fuch a (late the cubic foot of water weighs one 
thoufand ounces avoirdupois, and that of air 1.222, or -r'^ths 
nearly. ( See Water. ) There is not, however, any very exaft 
(landard in air, as the more water there is contained in the 
air, the heavier it mud of courfe be ; for indeed a confi- 
derable part of the weight of the atmofphere appears to 
arife from the water that is contained in it. Confequently, 
the nearer any water is found to approach the above (land- 
ards, the purer it may be concluded to be ; which may 
ferve to guide and direft many pradlical ufes and applica- 
tions of the fluid. 

In regard to the properties andeffefts of water, it is well 
known to be extremely volatile and expanfive, being capa- 
ble of reduftion wholly into the (late of vapour, and of 
being diifipated when expofed to heat and unconfined. In 



this (late, when properly confined, it is of great ufc and ap- 
plication for a variety of purpofes. See Steam. 

It is found, however, that water, when heated in an open 
veffel, acquires no more than a certain determinate propor- 
tion or degree of heat, whatfoever may be the intenfity or 
the length of continuance of the fire to which it is expofed ; 
which greateft proportion or degree of it is when it boils in 
the completell manner. The degree of heat, however, 
which is neceffary to make water boil perfeAly, is va- 
riable, according as the purity of the water, and the weight 
of the atmofphere, may happen to be. A knowledge of this 
may be of confidirable utility and benefit in the application 
of heat to this fluid, in a number of operations, as tending 
to fave time, trouble, and the confumption of fuel. 

The ready penetrability and feparability of water from 
the bodies with which it may have united, as well as its pro- 
perties and powers of cohefion, folution, and coagulation, 
render it ftill more extenfively|applicable and ufeful on many 

Water is a fluid which, in popular language, is dif- 
tinguifhed into many different kinds, according to the 
qualities of it, and the circumftances under which it 
makes its appearance, or is found (fee the preceding 
article Watek) ; m frr/h water, or that which is per- 
fedUy infipid, without any faline or other tafl;e, and ino- 
dorous, being that which is the natural and pure flate of 
water : in this ftate, it is well fitted for moll forts of domcf- 
tic as well as many other ufes : Aari/ water, or that in which 
foap does not completely or uniformly diflblve and diff'ufe 
itfelf, but appears in a fort of curdled or coagulated flate ; 
it is certain from this that the diffolving power of hard water 
is lefs than that of foft ; and that hence it is lefs fit for 
wafhing, bleaching, dyeing, boiling culinary vegetables, wa- 
tering plants and trees, and many other purpofes. It is, 
for the moft part, found, that the hardnefs of water pro- 
ceeds either from faline matters, or from the prefence of 
gas. The hardnefs which arifes from faline matters may 
moftly be difcovered and removed by the addition of fmall 
quantities, as a few drops, of a folution of fixed alkali ; 
and that which is caufcd by the latter by boiling, or ex- 
pofure to the open air for fome length of time. That the 
waters of fprings are hard ; but thofe of rivers foft. That 
hard waters are remarkably indifpofcd to corrupt ; they 
even preferve putrefciblc fubllances for a confiderable length 
of time ; hence thi'y would feem to be belt fitted for keep- 
ing, efpecial''.' as they are fo cafily capable of being foften- 
ed by a ve.y little of the alkaline folution being added to 
them. Putr'ifl water is that which has acquired an offenfive 
fmell and tatte by the putrefcence of the animal or vegeta- 
ble fubftances which are contained in it. This fort of water 
is of a very pernicious quality, and quite uniit for any pur- 
pofe. Cauftic lime, when put into water, is ufeful in prc- 
ferving it longer in a fweet ilate ; and even expofure to the 
air in broad fhallow veflels has the fame effeft. And water 
in this putrid ftate [may be, in a great meafure, rendered 
fweet by having a current of frefh air pafled through it, from 
the bottom to the top. Water in this condition is, of courfe, 
always to be avoided, except for the purpofe of manure, 
for which, in fome cafes, it is of great ufe. J?am-water, 
or that which may be confidered as a pure fort of diftilled 
water, but as impregnated during its paflage through the 
air with a confiderable quantity of putrefcent matter, 
whence, in fome meafure, its great fuperiority to any 
other m fertilizing the earth or foil, as well as in promoting 
the growth of trees and plants. Whence too its inferiority 
for Tome domcttic purpofes to that of the fpring or river 
kind, even where it can be readily and well procured ; but, 

more efpecially, fuch as is collefted and gotten from fpouts, 
trunks, and other contrivances put below the roofs of 
houfes and other buildings, which are the ufual modes of 
procuring it in this country, which is obvioufly very impure, 
and in a Ihort time becomes in the putrid ilate. From its foft- 
nefs, it, however, anfwers well in fome ufes, after it has 
become pretty pure by ftanding. /Jtrrr-water, or that 
which is next in ptirity to that of Tnow, or the diftilled kind, 
and which, for moft domeftic and fome other ufes, is fupe- 
rior to either of them, as having lefs putrefcent matter, and 
more fixed air, or carbonic acid gas in it. Of this water, 
that, however, which runs over a clean, rocky, (tony, or 
gravelly bottom, is by much the pureft. River-waters, in 
general, are/ound to putrefy fooncr than thofe of fprings ; 
and that during their putrefaftion they throw off a part of 
the extraneous matter they contain, and at length become 
fweet again, and purer than in their nrft ftate ; after which 
they wiD commonly preferve fweet a great length of time ; 
this is particularly the cafe with fome river-water, as that of 
the Thames. It is this fort of water that is fo extenfively ufe- 
ful in improving grafs-Iands, when thrown over them in a pro- 
per manner. See Watering Land, and Water Meadotv. 
There are fome other forts of water, zs/a/t water, or that 
which contains large portions of fait in it, fo as to be fenfi- 
ble to the tafte. This is of moft ufe in the preparation of 
that fubftance from it, but may perhaps be applicable in 
fome other ways, .y^j-water, or that which is a fort of an 
affemblage of bodies or fubftances, in which this fluid may 
be faid to have barely the principal part : it is, in fhort, an 
univerfal colledlion of moft of the matters in nature, fuftained 
and kept fwimming in this fluid as a medium or vehicle : 
being a diffufe folution of various fubftances, as common fait, 
bitter cathartic fait, diff^ercnt other faline matters, and a 
compound of muriatic acid with magnefia, mixed and blended 
together in a variety of proportions. It is capable of being 
frefliencd by fimple diftiUation, without any addition ; and 
is about three parts in a hundred heavier than common 
water ; the temperature of it at great depths being from 
thirty to forty degrees ; but near the furface it follows the 
temperature of the air more nearly. It is probable, from 
fome trials lately made with it, that it may be ufeful when 
applied to land in fome cafes. Its greater weight and other 
properties would feem to be favourable for this in fome in- 
tentions. It is the muddy material conveyed in the ftate of 
diffufion in this water, which is found fo beneficial in the 
warping of land in fome cafes and fituations. ( See Warp- 
ing of Land.) Snow-water, or that which is the pureft 
of all the common waters, when the fnow has been collefted 
in its pure ftate, and kept in a dry place, in clean glafs 
veflels, not clofely ftopped, but covered from duft and other 
fuch matters ; this water becomes in time putrid, although 
in well-ftoppcd bottles it will continue unaltered for fevcral 
years ; but diftilled water undergoes no alteration in either 
circumftance. Snow-water will be feen below to be ufeful 
in promoting the nutrition of plants. Spring-water, or that 
which is commonly impregnated with fome forts of mate- 
rials or other, as a fmall portion of impcrfeft neutral fait 
extrafted and taken up from the different ftrata through 
which it paffes and percolates ; great quantities of ftony 
matter, which are depofited as it runs along, and large 
maffes of ftone thus formed, fomeiimes too incrullating dif- 
ferent fubftances of the animal and vegetable kinds, which 
it is faid to petrify. Spring-water is much ufed for domef- 
tic purpofes in many cafes, and on account of its coolnefs 
and clearnefs forms a fuitable drink for man and animals ; 
but from its being ufualiy fomewhat hard, is inferior in 
fome intentions to that which has run a confiderable diftance 


in an open channel, expofed to the aftion and influence of 
the air. 

The water of fprings arifes and is caufed by rain, and 
from mifts and moifture in the atmofphere ; which falhng 
xipon the hills and higher grounds, as well as other parts, 
foak in and fink down into the earth, palTing along between 
the diflerent ftrata, until they find a vent or outlet in the 
form of a fpring. See Draining of Land, Spring, and 
WAtt. Alfo SvRlVG-Draimng. 

It is only under certain circumftances that fpring-water 
can be applied over the furface of grafs-land with much be- 
nefit ; as where it is confiderably impregnated and loaded 
with particular forts of materials, as thofe of the calcareous, 
and perhaps fome other kinds. 

A late philofophical writer has remarked, that the neceffity 
of much water in the progrefs of the growth of plants or 
their vegetation, is fhewn by the great quantity which exifts 
naturally in all parts of them ; infomuch that many roots, as 
thofe of the fquill and rhubarb, are known to lofe about fix 
parts out of feven of their original weight, fimply by dry- 
ing them before the fire ; which quantity of moifture never- 
thelefs does not exhale in the common heat of the atmo- 
fphere during the life of the root ; as may be feen in the 
growth of fquills in the fhop of the druggift, and of onions 
on the floors of the ftore-rooms of the feedfman. And 
that a fecond necelDty of much water in the economy of 
their vegetation or growth may be deduced from the great 
perfpiration of them, which appears from the experiments 
of Hales and others, who, like Sanftorius, have, it is faid, 
eftimated the quantity of perfpiration from their daily lofs 
of weight ; which, however, it is fuggefted, is not an ac- 
curate conclufion, either in refpeft to plants or animals, as 
they both abforb moifture from the atmofphere, as well as 
perfpire it. But that tnis great perfpiration of vegetables, 
like that from the fl'cin and lungs of animals, does not ap- 
pear to confift of excrementitious matter, becaufe it has in 
general no putrefcent fmell or tafte, but feems to be fecreted 
tirft for the purpofe of keeping the external furface of the 
leaves from becoming dry, which would prevent the oxygen of 
the atmofphere from entering into the vegetable blood or juice 
through them ; fince, according to the experiments of Dr. 
Prieftley on animal membranes, the oxygen will only pafs 
through them when they are moift. A fecond ufe of this 
great perfpiration is, it is faid, to keep the bark fupple by 
its moifture, and thus to prevent its being cracked by the 
motion of the branche* in the wind. And though a great 
part of this perfpirable matter is probably abforbed, as on 
the ildns of animals, yet as it exifts on fo large a furface of 
leaves and twigs, much of it muft neceffarily evaporate on 
dry and windy days. 

And the difcovery of the decompofition of water has, it 
is faid, led to a third great ufe of water in the vegetable 
economy, which is probably owing to its ready decompo- 
fition by their organs of digeftion, fanguification, or juice- 
forming, and fecretion. This is evinced, it is thought, firft, 
by the great quantity of hydrogen which exifts in the com- 
pofition of many of their inflammable parts ; and fecondly, 
from the curious circumftance which was firft difcovered by 
the ingenious Dr. Prieftley, that the water which they per- 
fpire is hyper-oxygenated, and in confequence always 
ready to part with its fuperabundance of oxygen, when 
expofed to the fun's light ; whence it may be concluded, it 
is thought, that a part of the hydrogen, which was pre- 
vioufly an ingredient of this water, has been feparated from 
it, and ufed in the vegetable economy. And that, from the 
decompofition of water, when confined in contaft with air 
beneath the foil, the nitrous acid feems to be produced, and 


ammonia, both of which are believed to be ufeful to vegeta- 
tion and the growth of plants. 

But that, befide thefe peculiar ufes of a great quantity 
of water, the more common ufes of it both to vegetable and 
animal life, along with caloric or the matter of heat, are to 
produce or preferve a due fupplenefs or lubricity of the fo- 
lids, and a due degree of fluidity of liquids which they 
contain or circulate ; and, laftly, for the purpofe of dif- 
folving or diffufing in it other folid or fluid fubftances, and 
thus rendering them capable of abforption, circulation, and 

It is beneficial, too, in the view of promoting the ferti- 
lity of grafs-lands, by the occafional fuffufion or flowing it 
over them, by which it not only fupplies fimple moifture for 
the purpofes above noticed in the drier parts of the feafon, 
but brings along with it calcareous earth and azotic air 
from the neighbouring fprings in many inftances, or other 
manures from the rivers and brooks. Still another benefi- 
cial confequence of it is to give a due penetrabihty to the 
foil or mould, which otherwife, in moft fituations, becomes 
fo ftiff and hard, as to ftop the elongation and diftenfion of 
the tender roots of plants ; but neverthelefs, the cohefion 
of the foil or earthy particles may be too much or too 
greatly diminifhed or leffened, by great and perpetual moif- 
ture, fo as not to give fufficient firmnefs to the roots of 
trees or plants. It may alfo be injurious in fome cafes, as 
in very hafty fhowers, by wafhing off and taking away 
much of the decompofing animal and vegetable recrements, 
which are foluble or dilfufible in it, and carrying them 
down the rivers and brooks into the fea ; and from the fides 
of hills, injury in this way is produced by fniall fhowers ; 
and the evaporation of water or moifture from the furface 
of the earth may produce fo much cold as to injure fuch 
terreftrial plants as are too long covered with it. 

The author of the " Elements of Agricultural Che- 
miftry" has concluded, that water is abfolutely neceffary to 
the economy of vegetation, both in its elaftic and fluid 
ftate ; and that it is not devoid of ufe, even in its folid 
form. Snow and ice are, it is faid, bad conduftors of heat ; 
and that, confequently, when the ground is covered with 
fnow, or the furface of the foil or of water is frozen, the 
roots or bulbs of the plants beneath are protefted by the 
congealed water from the influence of the atmofphere, the 
temperature of which, in northern winters, is ufually very 
much below the freezing-point ; and this water becomes the 
firft nourifliment of the plants in early fpring. The ex- 
panfion of water too during its congelation, at which time 
its volume increafes one-twelfth, and its contraftion of bulk 
during a thaw, tend, it is obferved, to pulverize the foil, to 
feparate the parts of it from each other, and to make it 
more permeable to the influence of the air, and the fibres of 
the roots of vegetables. 

Water alfo, as conftituting the daily neceffary drink of 
the different forts of domeftic animals which form the live- 
ftock of the farmer, is always to be particularly attended 
to, and to be provided as fully and of as good quality as 
can poffibly be met with ; as fuch ftock conftantly do beft 
where they have plenty of water. See Pond, and Live- 

Application of water, whether of ponds, brooks, rivers, 
or other kinds, to the purpofe of fifheries, is likewife a 
matter of great individual utility and benefit, as well as ge- 
neral national advantage. It is the means of increafing 
a moft ufeful fort of food in almoft an unlimited manner, 
at very little coft or expence. It provides much profitable 
labour and employment to fome of the working clalfes of 
fociety ; and from the trifling charge incurred in providing it, 
£ and 


and the readinefs of its difpofal, muft be a fource of great 
wealth to the country. It fhould, of courfe, be encouraged 
as much as poflible, wherever it can be done with conve- 
nience and fucccfs, in all parts of the kingdom. See FisH- 
PoaJ, PoND-/w/2), ricj, and SALMOS-Fi/heries. 

Water, Jjlenl of, in Hydraulics. See Ascent and 
Capillary Tubes. 

Water, High and Law. See Flux, High, and Tide. 

Watek, Motion of. The theory of the motion of run- 
ning water is one of the principal objefts of hydraulics, and 
many eminent mathematicians have apphcd themfelves to 
this fubjeA. But it were to be wifhed that their theories 
were more confiftent with each otlier, and with experience. 
The curious may confult fir Ifaac Newton's Princijjles, 
lib. ii. prop. 36. with the comment. Dan. Bernouilli's 
Hydrodynamica. Jo. Bernouilli, Hydraulica, Oper. tom. iv. 
p. 389, feq. Dr. Jurin, in die Phil. Tranf. N^452, and in 
Dr. Martyn's Abridg. vol. viii. p. 282, feq. S'Gravefande, 
Phyfic. Elem. Mathemat. Ub. iii. par, ii. Polenus, de Caf- 
tellis, and others. 

Mr. Maclaurin, in his Fluxions, art. 537. feq., has illuf- 
trated fir Ifaac Newton's doftrine on this intricate fubject, 
which ftill, notwithftanding the labours of all thefe eminent 
authors, remains in a great meafure obfcure and uncertain. 
Even the fimple cafe of the motion of running water, which 
is when it ilfues from a hule in the bottom of a vefTel kept 
conftantly full, has never yet been determined, fo as to give 
univerfal fatisfaAion to the learned. We (hall here mention 
fome of the phenomena of this motion, as ilated by Dr. 
Jurin from Poleni ; referring for other obfervations on this 
fubjccl to Fluids, and Hydraulic Laws of Fluids. 

1. The depth of the water in the vefTcl, and the time of 
flowing out being given, the meafure of the effluent water is 
nearly in proportion to the hole. 

2. The deptli of the water, and the hole being given, the 
meafure of the effluent water is in proportion to the time. 

3. The time of flowing out, and the hole being given, 
the meafure of the effluent water is nearly in a fubdupli- 
cste proportion to the height of the water. 

4. The meafure of the effluent water is nearly in a ratio 
compounded of the proportion of the hole, the proportion 
of the time, and a fubduplicate proportion of the depth of 
the water. 

5. The meafure of the water flowing out in a given time, 
is much lefs than that which is commonly afligned by ma- 
thematical theorems. For the velocity of effluent water is 
commonly fuppofed to be that which a heavy body would 
acquire in vacuo in falling from the whole height of the 
water above the hole ; and this being fuppofed, if we call 
the area of the hole F, the height of the water above the 
hole A, the velocity which a heavy body acquires in faUing 
in "vacuo from that height V, and the time of falling T ; and 
if the water flows out with this conftant velocity V, in the 
time T, then the length of the column of water, which 
flows out in that time, will be 2 A, and the meafure of it 
will be 2 A F. But if we calculate from Poleni's accurate 
experiments, we ihall find the quantity of water which flows 
out in that time to be no more than about 4-o J^ of this mea- 
fure 2 A F. Polen. de Cafteliis, art. 35. 38, 39. 42, 43. 

Poleni alfo found, that the quantity of water flowing out 
of a vcdel through a cylindrical tube far exceeded that 
which flowed through a circular hole made in a tliin lamina, 
the tube and hole being of equal diameter, and the height 
of tlic water above both being alfo equal ; and he found it 
to be fo when the tube was inferted, not into the bottom, 
which others had obferved before, but into the fide of the 
vefTel. 1 2 

6. Since the meafure of the water running out in the 
time T, is 2 A F X ; il-n, the length of the column of water, 
which runs out in that time, is 2 A x -ili-n- Therefore 
if each of the particles of water, which are in the hole in the 
fame fpace of time, paffcs with equal velocity, it is plain that 
the common velocity of them all is that with which the fpace 
2 A X ; J J would be gone over in the time T, or the ve- 
locity V X J.'i^t,. But tliis is the velocity with which water 
could fpring in vacuo to near -Jd of the height of the water 
above the ho!^-. 

7. But when the motion of water is turned upwards, 38 
in fountains, thefe are fcen to rife almoft to the entire height 
of the water in the ciftcrn. Therefore the water, or at leall 
fome portion of the water, fpouts from the hole with almoft 
the whole velocity V, and certainly with a much greater ve- 
locity than V X fo t'tt- 

8. Hence it is evident, that the particles of water, which 
are in the hole in the fame point of time, do not all burft 
out wit!) the fame velocity, or have no common velocity ; 
though fome mathematicians have hitherto taken the con- 
trary to be certain. 

9. At a fmall diilance from the hole, the diameter of the 
vein of water is much lefs than that of the hole. For in- 
ftance, if the diameter of the hole be 1, the diameter of 
the vein of water will be Ji, or 0.84, according to fir Ifaac 
Newton's meafure, who firll obferved tliis piienomenon ; 

and accordine: to Poleni's meafure — ;, or -— -, tliat is, takinti- 
^ 26 26 *' 

the mean diameter 0.78, nearly. 

As to the manner of accounting for thefe phenomena, we 
have already obferved that authors are not agreed ; and 
it would be far beyond our defign to ilate their different 
theories, we muft therefore refer to the originals above 

Neither are authors agreed as to the force with which a 
vein of water, fpouting from a round hole in the fide of a 
veflel, prelfes upon a plane direftly oppofcd to the motion 
of the vein. Moll authors agree that the prelfure of this 
vein, flowing uniformly, is equal to the weiglit of a cylin- 
der of <\ater, the bafis of which is the hole through which 
the water flows, and the height of which is equal to the 
height of the water in the veifel above the hole. The ex- 
periments made by Mariotte, and others, feem to counte- 
nance this opinion. But Mr. Daniel BcrnouiUi rejefts it, 
and ellimates this preiliire by the weight of a cylinder, the 
diameter of which is equal to tlie contraftcd vein (accord- 
ing to fir Ifaac Newton's obfervation above-mentioned), 
and the height of which is equal to twice the height of the 
water above the hole, or, more accurately, to twice the al- 
titude correfponding to the real velocity of the fpouting 
water ; and this prifFure is alfo equal to tlie force of repul- 
fion, arifing from the readlion of the fpouting water upon 
the veflel. For he fays that he can demonllrate, that this 
force of repulfion is equal to a pren"ure exerted by a vein of 
fpouting water upon a plane dirc£\ly oppofcd to its motion, 
if the whole vein of water ftrikcs perpendicularly againd tlie 
plane. From whence it would follow, that the prcflure or 
force of the vein will be greater in proportion, as its con- 
traction is lefs ; and this contraclion vaniihiiig, as it does 
when the water fpouts througii a Ihort tube, and the vein 
being at the fame time fuppofed to have the whole velocity 
it can acquire by theory, the fpouting water will then exert 
a prefl^ure double to what is commonly fuppofed. But the 
aftual velocity of the water being always fomething lefs 
than it ought to be by theory, and the vein of water 
beiog not uncommonly contracted to ahtiotl one half, expe- 


riinents have led authors to think, that the prefTure, exerted 
by fpouting water, was equal to the weight of a cylinder 
■of the fame diameter with the vein, and of the height of the 
water above the hole. The ingenious author remarks that 
he fpeaks only of fingle veins of water, the whole of which 
are received by the planes upon which they prefs ; for as to 
the prelTures exerted by fluids furrounding the bodies they 
prefs upon, as the wind, or a river, the cafe is different, 
though confounded with the former by writers on this fub- 
jeft. Hydrodynamica, feft. 13. p. 289. 

M. Bernouilli endeavours to confirm his theory by a dif- 
fertation in the eighth volume of the A<fta Petropolitana ; 
where he obferves, that the experiments formerly made be- 
fore the Academy of Sciences at Paris, to eftablifli the 
quantity of the prefTure exerted by a vein of fpoutmg 
water, are very far from proving the truth of the rule they 
are brought to eftablifh. For inilance, in one of thofe ex- 
periments, the height of the water in the vefTel above the 
hole from whence the vein fpouted was two feet Paris mea- 
fure ; the diameter of the circular hole, wiiich was cut in 
the horizontal bottom of the vefTel, was four lines ; and the 
force of the vein of water was obferved to be one ounce 
and three-quarters. But the weight of a cylinder of water 
of the diameter of the liole, and of the heiglit of the water 
in the veJTel, is fcarce equal to one ounce and three-eighths. 
The difference, therefore, is at leafl three-eighths of an ounce, 
which is about tliree-elevenths of the whole weight of the 
before-merftioned cylinder of water. So that it is furprif- 
ing, that this difference fhould have been afcribed to the re- 
moval of the plane, receiving the impulfe, to fome diflance 
from the hole ; for this caufe, fuppofing the plane removed 
to the diftance of two inches, could not produce an increafe 
of one-iixteenth of an ounce. It appears, therefore, that 
the common opinion is rather overturned than confirmed by 
experience. Du-Hamel, Hift. Acad. Paris, ann. 1679, 
feft. 3. cap. 5. 

M. Bernouilh, on the other hand, thinks his own theory 
fufficiently eftablidied by the experiments he relates ; for 
the particulars of which, we refer to the Afta Petropoh- 
tana, vol. cit. p. 122, feq. 

This ingenious author thinks that his theory of the quan- 
tity of the force of repulfion, exerted by a vein of fpouting 
water, might be ufefully applied to move fhips by pumping; 
and he thinks the motion produced by this repuUive force 
would fall little, if at all, fhort of that produced by rowing. 
He has given his reafons and computations at length in his 
Hydrodynamica, p. 293 to 302. 

The fcience of the prefTures exerted by water, or other 
fluids in motion, is what M. Bernouilli calls hydraulko-Jlatka. 
This fcience differs from hydroilatics, which confiders only 
the prefTure of water and other fluids at reft ; but hydrau- 
lico-ftatics confiders the prefTure of water in motion. Thus 
the prefTure exerted by water, moving through pipes, upon 
the fides of thofe pipes, is an hydraulico-flatical coniidera- 
tion, and has been erroneoufly determined by many, who 
have given no other rules in thefe cafes, but fuch as are ap- 
pUcable only to the prefTure of fluids at reft. See Hydro- 
dynam. feft. 12. p. 256. feq. 

Water, Rai/Ing of. Machines for this purpofe arc 
fo numerous, that a minute defcription of fuch hydraulic 
machines as are in common ufe would fill a volume ; and 
a fcientific account of their principles, with the maxims 
necefTary to be obferved in their conftruftion, would 
form a very complete body of mechanical fcience : this is 
far beyond the limits of an article hke the prefent, in which 
we can only introduce the mofl ftriking machines which 

have not already been explained in different articles of this 
work ; and for others, we muft refer to the original works 
in which they are defcribed. 

The moft complete coUedlion of hydraulic mactiines is 
that of Jacob Leopold, entitled " Theatrum Machinarum 
Hydraulicarum," publifhed at Leipzic, in 1724 and 1725, 
in 2 vols. foHo ; thefe form part of his voluminous " Theatri 
Machinarum," which maybe confidered as containing all that 
was known in mechanics at that period. 

M. Belidor, in his " Architefture Hydrauhque," 1737, 
has defcribed many machines which were invented fince the 
date of Leopold's work. This eminent engineer was a 
good mathematician, and his work may be confidered as a 
ftandard for the theory of the hydraulic machines of which 
it treats. The " Experimental Philofophy" of Defagu- 
liers contains fome chapters on hydrauhc machinery, in 
which he generally follows Belidor very clofely, but has 
tranflated the mathematical inveftigations of the former into 
the ordinary procefTes of arithmetic, to adapt them to the 
comprehenfion of mechanics ; and in this point of view, the 
works of Defaguliers have been of great ufe. On the 
other hand, M. Prony publifhed a modern edition of Beli- 
dor's work in 1 790, in which, in moft cafes, he has tran- 
fcribed the procefTes of the original into the modern modes 
of analyfis ; but on the whole, he has added httle to our 
real knowledge, except his defcriptions and fuperb plates of 
Mr. Watt's fteam-engine. 

We do not recoUeft any complete coUefkion of machines 
for raifing water fince Behdor, although the inventions of 
the laft century are both numerous and important. Much 
information relative to them may be derived from Gregory's 
" Mechanics," in 2 vols. 8vo. ; Dr. Robifon's Works, and 
his excellent articles Hydrodynamics, Pump, and Water- 
works, in the Encyclopaedia Britannica ; and from various 
mifcellaneous publications, fuch as the Repertory of Arts, 
and the TranfaAioi.s of different learned Societies ; alfo the 
colleftion of Mr. Smeaton's Reports, in 3 vols. 4to. It 
is much to be regretted, that this excellent engineer never 
completed a defign which he formed, to publifh a com- 
plete colleftion of praftical hydraulic machines founded 
on his own experience. Among his manufcript papers which 
have been lent to us by fir Jofeph Banks, we find an outline 
for this work, of which we have availed ourfelves in this article. 

In confidering machines for raifing water, they may be 
clafTed under two heads : 

Firft, thofe machines which aftuate fome kind of 
bucket or veffel adapted to contain water, which vefTel is 
raifed up when full of water, and difcharges its contents 
into an elevated refervoir, then defcends empty in order 
to repeat its aftion : of this fpecies are, the buckets for 
wells, fcoops, Perfian and Chinefe wheels, chaplets or 
chains of buckets, the Noira, and the fcrew of Archimedes. 
It is evident from the nature of all this clafs, that they are 
incapable of raifing water to a greater height than that to 
which the machine is elevated, or provided with the means 
of drawing up the buckets or other veffels ; and further, 
that they cannot raife conftant ftreams of water, but that 
the water muft be given out by a fucceffion of difchargas 
from the different buckets or veffels. 

The fecond clafs compriies thofe machines which aft by 
means of valves and piftons moving in cylinders, or other 
equivalent contrivances, and force the water to afcend 
through pipes or tubes : thefe machines have the advantage 
of raifing the water to very great heights above the place 
where the machine is placed. The greater part of thefe 
machines we have already defcribed under the article Pump, 
E 2 and 


and there remain but few to be confidered in the prefent 
article ; viz. the varieties of the hydraulic ram, of the 
Chremnitz fountain, and of the fyphon machines. 

The moll obvious means of raifing water is by the operation 
called babng, that is, lifting up water in a bucket, or other 
Tcflel, by the force of a man's arm. This method is ex- 
tremely fatiguing, and is only adapted to very fmall eleva- 
tions, fuch as clearing the water from a boat, &c. The mod 
ancient hydraulic machine afts on this principle, fuch as the 
fcoop aiid troughs, the Fen wheel, Perfian wheel, tiie Noira, 
&c. : it is, therefore, with tliefe machines we fliall com- 

The Dutch tvatrr-fceop, or (hovel, is the bed means of 
baling out water. The fcoop is a kind of box, made of 
five pieces of board, with one end and one fide open : this 
box is fixed at the extremity of a long pole, wliich the 
workman holds in his hand, and the weight of the fcoop 
is borne by a cord tied to the pole near to the box, and 
fufpended from a tripod, formed_of three poles tied together 
at the top. The man works the machine by fwinging the 
fcoop backwards and forwards in the direAion of the length 
of the pole ; in moving the box forwards, he depreffes the 
end of the pole, which caufes the box to dip into the water, 
and take up a quantity which it will throw forwards and 
rather upwards to a confiderable diltance. In bringing the 
fcoop back for another (Iroke, he depreffes the end of the 
pole which he holds in his hand, and thus keeps the box 
out of the water. Of courfe this method is only applicable 
where the height to which the water is to be raifed, or rather 
tlirown, is very fmall. M. Behdor informs us, that a work- 
man can only remove half a cubic foot in two vibrations, 
which he will perform in four feconds ; this is at the rate 
of 7^ cubic feet per minute, or 4J0 cubic feet per hour : it 
is rarely applicable, except to throw the water over a bank 
which forms the boundary of a ditch, or other place of fmall 
depth, which is to be emptied. 

The laving gun, which is ufed in falt-works from its fim- 
plicity, comes next. It is a trough of five or fix feet in length, 
made fmall at one end hke a fpout, and gradually incrcafing to 
the oppofite end, where it is about a foot or eighteen inches 
fquare. The fmall end is fupportedon pivots upon the bank 
over which the water is to be raifed, and a lever is applied to 
it for a man to work it by. The large end of the trough 
will dip into the water, when it defcends and becomes filled ; 
but when hfted the leaft above the horizontal pofition, the 
contained water will run along the trough, and be delivered 
over the bank through the fpout. This machine is much 
improved by making it double, or with two troughs, on the 
oppofite fides of the centre ; thus when one alcends, the 
other will defcend fo as to raife up a conftant dream, which 
it mud, in this cafe, deliver at a fpout fideways, near to the 
pivot or centre on which it plays. This double macliine 
will raife a copious dream of water, but is confined to fmall 
heights of three or four feet. If the large end of the 
trough has a valve opening into it to admit the water, it will 
fill itfelf more readily. A machine which operates on the 
fame principle as'tjiis, is called the fcoop-wheel, or tympa- 
num, which is in faft feveral double laving machines ar- 
ranged round the centre like a wheel. The advantage of 
this wheel is, that it always moves in the fame direftion, 
whereas the fimplc machine requires a reciprocating 

The tympanum, or /coop-<w/)eel, mentioned by Vitruvius, is a 
great hollow wheel formed by a kind of barrel or drum 
(as its name imports] : it is compofed of feveral planks 
joined together, well ca>ilkcd and pitched, and having a ho- 

rizontal axle with pivots at the ends, on which it turns. The in- 
terior capacity of this drum is divided into eight equal fpacc?, 
by as many partitions placed in the dircflions of the radii ; each 
fpace or cell has an orifice of about fix inches in width in tlie 
rim of the drum or wheel. Thefe openings are fo (haped, as to 
facilitate the admifTion of the water ; moreover, there are 
eight hollow channels running along the axle of the wheel and 
contiguous to each other, each correfponding to one of the 
eight large cells ; into thefe channels tlie water paiTesout of the 
cells juft mentioned, and after running along thechannels in the 
axis of the wheel to a convenient dillance, it efcapes through 
orifices into a refervoir placed jud under the axle. Thus 
when the wheel is turned round, the water is elevated through 
a vertical height equal to the radius of the hollow wheel. 

When the tympanum is ufed to raife water from a run- 
ning dream, it is moved by means of float-boards fixed on the 
circumference, which are impelled by the dream ; but when 
it is employed to raife dagnant waters, there is commonly a 
fmaller hollow wheel fixed on the (haft at the fide of the 
tympanum, which is turned by men walking in it, as in the 
old walking-crane. The chief defeft of this machine is, 
that it raifes the water in the mod difadvantagcous fituation 
polTible, for the load of water is always towards the extre- 
mity of a radius of the wheel, and the length of the effec- 
tive lever which anfwers to it mud continually increafe as 
the water is raifed through the whole quadrant, which the 
water defcribes in paffing from the bottom of the wheel to 
the altitude of its centre, fo that the power mud aft in the 
fame manner as if it were applied to a winch or crank han- 
dle, and cannot aft uniformly. 

Tlie horn-v)heel was contrived to remedy this defeft : it 
is fo called, becaufe the fegments which pafs from the cir- 
cumferences of the large flat cylinder to its centre are not 
draight radii, as in the former indance, but are curved fpirally. 
The fcoops, or mouths, by turns, dip into the water, and 
as they rife up caufe the water to pafs up the horn, or 
curved feirmcut, until it is as high as tlie centre of the 
wheel, and then it is difcharged into a trough placed under 
the end of the axis, which is hollow, and has its pivot* 
fadened to a crofs. 

M. de la Faye has invedigated the proper curves for the 
fcoop fegments of this machine in the following manner : — 
When we evolve the circumference of a circle by unwrapping 
a dring from the circumference, the end of the dring will 
defcribe a curve called tlie involute of the circle, of which 
all the radii are fo many tangents to the circle, as is (hewn 
by the dring in its different pofitions whild tracing the 
curve, and likewife all the radii are refpeftively perpen- 
dicular to the feveral points of the curve defcribed by the 
end of the dring. 

The greated radius of this curve is a line equal to the 
periphery of the circle evolved. The truth of this daie- 
ment is (hewn by geometricians, when treating of the gene- 
ration of Evolute and Involute Curves. See thole articles. 

Hence, having an axle, whofe circumference a little ex- 
ceeds the height to which the water is propofed to be ele- 
vated, let the circumference of the axle be evolved, and it 
will make a curve which will be the involute of the circle, 
as before mentioned. Now, let a number of pipes, or 
trunks, be made exaftly with tiiis curvature, and then put 
together around the axle, in form of a wheel, fo that the fur- 
ther extremities of thefe canals will fucceffively enter the wa- 
ter that is to be elevated, whild the other extremities abut 
upon the (haft which is turned. Then, in the courfe of the 
rotation of the wheel, the water taken in at the extremity 
of each canal will rife in a vertical line, wliich is a tangent 


to the fliaft, becaufe the curves of the feveral channels will 
be at right angles to this vertical line, in the points where 
the line interfefts the curves ; and this is true in whatever 
pofition the wheel may be. Thus the aftion of the weight 
continuing always beneath the extremity of the horir'ontal 
radius of the axle, will oppofe the fame refiftance, as though 
it afted upon the invariable arm of a lever, in the manner 
of a bucket of water, which is drawn up out of a well by a 
rope, winding on a roller, and the power required to raife 
the weight will be always the fame. 

If the radius of the wheel, of which thefe hollow canals 
ferve as bent fpokes, be equal to the height through which 
the water is to be raifed, and confequently equal to the 
circumference of the axle, or (haft, the power will be to 
the load of water reciprocally as the radius of a circle to 
its circumference, or direftly as I to 6^ nearly. M. de la 
Faye recommended the machine to be compofed of four of 
thefe canals, but it has often been conilrufted with eight. 
The wheel is turned by the impulfion of the ftream upon 
float-boards fixed on the circumference of the wheel, and 
the orifices of the curvilineal canals dip one after another 
into the water which runs into them ; and as the wheel 
revolves, the fluid rifes in the canals, until it is as high as 
the centre ; it then runs out in a ftream from the holes in 
the axis, and is received into the trough fixed beneath the 
jixis ; from thence it may be conveyed by pipes or troughs 
to the required fituation. 

By this conftruftion, the weight to be raifed offers always 
the fame rt-fi (lance, and that is the leaft poffible, while the 
power is applied in the moft advantageous manner which 
the circumltances will admit of. Thefe conditions being 
both fulfilled at the fame time, furnifh the moll defirable 
perfeftion in a machine. This machine raifes the water by 
the fliorteft way, namely, the perpendicular or vertical line, 
and in this refpetl is preferable to Archimedes's fcrew, 
where the water is carried up a crooked and inclined path ; 
and befides this each curved channel in this wheel empties all 
the water it receives in every revolution, vvhile the fcrew of 
Archimedes delivers only a fmall portion of the fluid with 
which it is charged, being often loaded with twenty times as 
much water as is difcharged at one rotation, and thus re- 
quiring an increafe of labour when a large quantity is in- 
tended to be raifed by it. The horn-wheel would be one 
of the moft perfeft machines for raifing water, were not its 
powers confined to fuch altitudes as the femi-diameter of 
the wheel. 

The fiajh, or fm-ivheel, comes next to be defcribed. — 
This is a vertical wheel, made exailly like thofe water- 
wheels for turning mills which are called breaft-wheels, and 
in the fame manner the wheel is furrounded at the lower 
quadrant by a curved fweep of mafonry or breaft, to which 
the floats of the wheel are fitted with the greateft accuracy, 
but do not abfolutely touch. This wheel, being turned 
round in a direftion contrary to that in which a water-wheel 
turns, will carry water before its floats, and raife it up 
againft the breall until it runs over the fame. The opera- 
tion is juft the reverfe of the water-wheel ; and the only 
difference in the conftruftion of the two machines is, that 
the flalh-wheel requires no ftiuttle to be placed at the top 
of the breaft, becaufe the water mull be allowed to run 
freely away from the top of the breaft ; but the water- 
wheel requires a Ihuttle or fluice to regulate the quantity of 
water which ihall flow to the wheel. 

It is by this kind of machine that the extenfive fens of 
Holland are drained ; and in Lincoln and Cambridgefliire 
they are alfo ufed very extenfively. They are, in general, 

worked by the power of the wind, and are on a very large 

Mr. Smeaton made a horfe-machine on this plan, which 
raifed thirty-three hogflieads per minute, to the height of 
four feet and a half, when it wa •. worked by four horfes ; 
but a fluice was placed in the channel which admitted the 
water to the wheel, fo as to fupply the water in a greater 
or leffer quantity ; and by this means, the fame machine 
could he adapted to the power of three or two horfes. 
The crown or top of the breaft, over which the water 
was dehvered, was not elevated to the full height to Avhich 
the water was to be raifed, but it was laid twelve inches 
beneath the furface, and the body of water which the wheel 
raifed up was fufficient to drive this depth of water before 
it ; but to prevent the return of the water when the mill 
ceafed working, two pointed doors were placed in the 
channel leading from the wheel, like the gates of a canal- 
lock : thefe doors opened freely, to let the water pafs, but 
would fhut and ftop the water from returning. The pro- 
portions of this machine were as follows : 

Diameter of the track in which the 7 e c o ■ l 
horfes walked - - .} 26 feet 8 inches. 

Great cog-wheel fixed on the per-l 72 teeth 9 feet dia- 
pendicular axis - . . J meter. 

Trundle worked by the wheel - 35 teeth 4^ feet diam. 

Diameter of the water-wheel on the ) r 
fame axis as the trundle - j '4 ^^ • 

Breadth of the wheel ... 2 feet 2 inches. 

Number of its floats - - - 42 

The floats did not point to the centre of the wheel, but 
formed tangents to a radius, equal to about half the radius 
of the wheel. The floats of the wheel were very exaftly 
fitted to the channel or pit in which it worked, fo as not 
to touch. 

The bucket-'wheel is a very ancient method of raifing 
water ; but it cannot lift water to a greater height than its 
own diameter. The laft machine was the reverfe of the breaft 
water-wheel, and the prefent is the reverfe of the over-fhot 
water-wheel, for the circumference of the wheel is furround- 
ed by buckets, which dip in the water beneath the wheel, 
and take up water, which they difcharge at the top of the 
wheel into an elevated trough or refervoir. The wheel is 
mounted upon an horizontal axis, and turns upon pivots ; it 
is put in motion by the force of a current of water ftriking 
the float-boards fixed on the circumference of the wheel ; 
or if there is no current in the water, it may be moved by 
making the wheel hollow within for a man to walk in it, as 
is common in fome kinds of cranes, or the wheel may be 
turned by horfes. The rim, or circumference of the wheel, 
is made hollow, and is divided into feveral compartments, to 
form a number of boxes or buckets ; each bucket has an 
opening into it at that end which will be the moft advanced 
when the wheel turns ; and from this opening, a fpout or 
trough projefts in a direftion parallel to the axis of the 
wheel. When the wheel revolves, the buckets dip into the 
ftream, and become filled with water ; but as the mouths 
or fpouts are at the upper end when the buckets rife out of 
the water, they cannot efcape, and each bucket carries up 
its charge of water to the top of the wheel ; but the buckets 
will have then become inverted, and the fpouts or openings 
being at the lowelt part, that they difcharge the water 
fideways through the fpouts into a trough properly placed 
to receive it, and then the buckets defcend empty till they 
dip into the ftream and are refilled. The objeftion to this 
machine is, that the buckets begin to pour out the water 



fome time before they arrive at the greateft height of the manner, that they will (land in correfpondigpr pofitions in 
wheel ; and, therefore, the trough is of neceflity placed every quarter of the circle. Suppofe vertical lines drawn 
lower than the diameter of tiie wheel, or a confiderable por- through the centre of motion of each bucket in the rifmg 
tion of the water would be loft, and in any cafe part of the part of the wheel, and they will interfic't the horizontal 
water is raifed above the level of the trough. diameter of the wheel in points, at which, if the buckets 

Spanifh Bucket-Wheel. — Mr. Townfend, in his Travels were hung, they would make the fame refiliance to the 
through Spain, defcribcs a fimple machine which is ufed at moving force, as they do when hanging at their refpeAive 
Narbonne for watering of gardens. The water is raifed by a places on the rim of the wheel. Thus, fuppofing there are 
vertical wheel, which is twenty feet in diameter, on the cir- eighteen equidiif ant buckets, then while eight hung on each 
cumference of which is fixed a number of little boxes or fide of a vertical diameter of the wheel, there would be eight 
fquare buckets, for the purpofe of raifing water out of the on the other fide, and two would coincide with that diamc- 
ciftcni communicating with the canal below, and to empty ter : in this cafe, tlie refiftance arifing from all the full 
it in a refervoir above^ placed by the fide of the wheel. The buckets would be the fame as if one bucket hung on the 
buckets have a lateral orifice to receive and to difcharge the prolongation of the horizontal diameter, at the diftance of 
water. The axis of this wlieel is embraced by four fmall twice the fine of 20° + twice the fine of 40° + twice the 
beams, crofling each other at right angles, and tapering at fine of 60° + twice the fine of 80°, thefe being the fines to 
the extremities fo as to form eight little arms. This wlieel the common radius of the wheel. 

is near the centre of the path in which the mule vialks, and To know tli.- quantity of water that each one fhould con- 
contiffuous to the vertical axis, into the top of which the tain, take four-nintiis of the abfolutc force of the ftream, 
horfe-beam is fixed ; but near the bottom of this axis it is that is, four-ninthr, of the weight of a prifm of water whofe 
embraced by four little beams, forming eight arms, fimilar to bafc is the fiirface of one of the float -boards, and whofe 
thofe above defcribed, on the axis of the water-wheel. As height is equal to that through which the water muft fall in 
the mule which they ufe goes round, thefe horizontal arms, order to acquire the velocity with which the ftream moves, 
fupplying the place of cogs, take hold each in fucceflion of This is the power which fhould be in equilibrio with the 
thofe arms which are fixed on the axis of the water-wheel, weight of water contained in the buckets of the rifing femi- 
and keep it in rotation. This machine may be made very circle. Then fay, as the fum of the fines mentioned above 
cheap, and will throw up a great quantity of water, yet is to the radius of the wheel to the centre of the float- 
undoubtedly it has two defefts ; the firft is, that part of the board, fo is the power juft found to a fourth term, one-half 
water runs out of the buckets, and falls back into the well of which will be the weight of water that ought to be con- 
after it has been raifed nearly to the level of the refervoir ; tained in each bucket. Laftly, the velocity of the float- 
and the fecond is, that a confiderable proportion of the water board of the wheel will be to that of the ftream nearly as 
to be difcharged is raifed higher than the refervoir, and falls one to two and two-fifths, and from this the number of re- 
into it only at the moment when the bucket is at the higheft volutions it will make in any determinate times may be 
point of the circle, and ready to defcend. known, and of confequence the quantity of water the wheel 

The Perfian -wheel with ftuinging.buciets is free from fome will raife in the fame time, fince we know the capacity of 
of the defetts of the laft machine. The buckets are loofe, each bucket, and the number of them which will be dif- 
and each hangs from tlie circumference of the wheel by a charged in every revolution of the wheel. Sec Persian 
pin, on which it fwings or turns freely ; and as the bucket Wheel. 

is fufpended by its upper part, it will hang perpendicular, The Ch'mefe Buclit-Wheel. — Sir George Staunton, in his 
with the mouth upwards, in all pofitions of the wheel. From account of the Embaffy to China, gives the following de- 
the time it dips in the water and is filled, until the bucket fcription of a bucket -wheel, which is different from any we 
arrives at the upper part of the wheel, it is carried by the have met with in the hydraulic collections, and conftrufted 
motion of the wheel againft the edge of the trough, and in- with that fimplicity which diftinguifties the Chincfe inven- 
clined fo far as to difcharge its contents into the trough, tions. Two hard-wood pofts or uprights are firmly fixed in 
(See Persian Wheel.) The pins are fixed into the circum- the bed of the river, in a line perpendicular to its banks, 
ference of the wheel, and projeft fideways therefrom a fuf- Thefe pofts fupport the pivots of an axis of about ten fert 
ficient diftance to fupport the buckets, and carry them over in length : tliis is the axis of a large wheel confifting of 
the elevated trough. Sometimes the wheel is made with two unequal rims, the diameter of the rim whicli is neareft 
two rims, and each bucket is fufpended upon an axis be- to the bank being about fifteen inches lefs than that of 
twecn them : the end of each axis paffes through the rim of the outer rim ; but both ri.iis dip into the ftream, while the 
the wheel, and is bent to form a fhort lever, which is carried oppofite points or top of the wheel rife above the elevated 
by the motion of the wheel againft a fixed rail, and thus bank over which tlie water is to be raifed. This double 
inclines the bucket to difcharge tlie contents into a trough wheel is framed upon the axis, and is fupported by fixtecn 
which is fixed to the rims of the wheel immediately beneath or eighteen fpokes, inferted obliquely int.) the axis near each 
the bucket, and has a fpout projefting at the fide of the extremity, and crolTing each other at about two-thirds of 
wheel, to carry the water fideways and dehver it into the their length. They are there ftrengthened by a concentric 
trough, which is fixed at the fide of the wheel for its circle, and are fattened afterwards to the two rims. The 
reception. fpokes inferted in the interior extremity of the axis reach to 

As the Perfian wheel is a very effcftive machine in fitua- the outer rim, and thofe proceeding from the exterior cx- 
tions where the elevation is required to be but fmall, the tremity of the axis reach to the inner and fmaller rim. Be- 
foUowing direttions, given by M. Bclidor for its conftruc- tween the rims and the crofGngs of tlie fpokes is a triangu- 
tion, are worthy of attention: firft fix the diameter of the larfpace, which is woven with a kind of clofebafl<et-work, to 
• wheel fomething greater than the altitude to which the water ferve as ladle-boards, or floats. Thefe fuccefTively receiving 
is to be raifed ; fix alfo upon an even number of buckets, to the current of the ftream, obey its impulfe, and turn round 
be hung at equal diftances round the periphery of the wheel ; the wheel. 

and mark the pofition of their centres of motion in fuch a The buckets which take up the water arc fmall tubes or 

fpout 9 


fpouts of wood attached to the two rims of the wheel, and 
having an in«lination of about twenty-five degrees to the 
horizon, or to the axis of the wheel. The tubes are clofed 
at their outer extremities, which are fixed to the larger rim, 
and open at the oppofite end. By this pofition the tubes, 
which in the motion of the wheel dip into the ftream, have 
their mouths or open ends uppcrmoll, and fill with water. 
As that fegment of the wheel rifes upwards, the moutlis of 
the tubes attaclied to it will alter their relative inclination, 
but not fo niucii as to let their contents flow out until fuch 
fegment of the wheel arrives at the top. The mouths of 
thefe tubes are then relatively deprefled, and they pour the 
water into a wide trough placed on pivots, from whence it 
is conveyed, as may be wanted, among the plantations of 

The only materials employed in the conftruftion of this 
water-wheel, except the nave or axis, and the pods on 
which it reits, are afforded by the bamboo. Tiie rims, the 
fpokes, the ladle-boards or floats, and the tubes or fpouts, 
or even the cords, are made of entire lengths, or fingle 
joints, or large pieces, or thin flices, of the bamboo. Nei- 
ther nails, nor pins, nor fcrews, nor any kind of metal, 
enter into its conftruftion : the parts are bound together 
firmly by cordage of flit bamboo. Thus, at a very trifling 
expence, is conllrutled a machine, which, without labour 
or attendance, will furnifh, from a confiderable depth, a 
refervoir with a conftant fupply of water, adequate to every 
agricultural purpofe. 

Thefe wheels are from twenty to forty feet in diameter, 
according to the height of the bank, and conicquent eleva- 
tion to which the water is to be raifed. A wheel of thirty 
feet is capable of fuftaining with eafe twenty tubes or 
fpouts, of the length of four feet, and diameter of two 
inches in the clear. Ths contents of fuch a tube would be 
equal to fix-tenths of a gallon, and the twenty tubes would 
hold twelve gallons. A fl;ream of a moderate velocity 
would be fufficient to turn the wheel at the rate of four re- 
volutions in one minute, by which would be lifted forty- 
eight gallons of water in that fiiort period ; or in one hour, 
two thoufand eight hundred and eighty gallons ; and fixty- 
nine thoufand one hundred and twenty gallons, or upwards 
of three hundred tons in a day. This wheel is thought by 
fir George to exceed, in mod refpefts, any machine yet in 
ufe for fimilar purpofes. The Perfian wheel, with loofe 
buckets fufpcnded to the edge of the rim or fellies of the 
wheel, fo common in the fouth of France, and in. the Tyrol, 
approaches neareft to the Cliinefe wheel, but is vaftly more 
expenfive, and lefs fiuiple in its conilrudlion, as well as lefs 
ingenious in the contrivance. In the Tyrol there are alfo 
bucket-wheels for hfting water in a circumference of wood, 
hollowed into fcoops ; but they are much inferior either to 
the Perfian or Chinefe wheel. 

Chain of Buckets. — This machine confifts of a number of 
buckets attached to a chain or rope, the ends of which are 
united together. The chain is condufted over a wheel, 
which is turned by fome animal or mechanical power ; and 
the chain hangs down from this wheel into the well from 
which the water is to be drawn. The buckets at the lower 
part of the chain become filled, and, by the motion of the 
chain, the buckets attached to one part of the chain will 
afcend full of water, whilft thofe on the oppofite fide are 
dcfcending empty, with their mouths downwards. When 
the full buckets of water turn over the upper wheel, they 
difcharge their contents into a trough fixed near the wheel. 
The moft convenient way of difcharging the water is to 
inake the upper wheel hollow, with divifions in it like the 
tympanum ; and the buckets, when they turn over, will 

pour their contents into the hollow fegments of the wheel, 
and it will run off through a hollow in the axis made for 
that purpofe. The advantage of the chain of buckets over 
the wheel is, that the chain can be made to dcicend in a well, 
or fmall fpace, where the wheel could not ; alfo, that the 
chain may be ufed for greater depths than would be praAi- 
cable for a wheel. 

The Spani/h noira is a chain of buckets or earthen jarsk 

Mr. Townfend informs us, in his journey through Spain, 
that the noira confifts of an endlefs band or girdle, paffing 
over a fprocket-whcel : the band is long enough to reach 
eighteen inches or two feet below the furface of water in a 
well. All round this band, at the diftance of about fifteen 
inches, are fixed jars of earthen-ware, which, as the band 
turns, take up water from the well, and pour it into a cif- 
tern fitted to receive it. A little afs, going round in a 
circular walk with eafe, turns a trundle, which gives motion 
to a cog-wheel, fixed on the fame axis with the fprocket- 
wheel, on which the band is hung, and with which it turns. 
This machine produces a conftant and confiderable fupply 
of water, at a fmall expence, and with very little friftion. 
As the air would obftruft the entrance of water into thefe 
earthen jars or bottles, each jar has a little orifice in its bot- 
tom, through which the air efcapes ; but then water runs 
out alfo, and a certain quantity falls back into the well. 

It is true, as the jars rife in one llraiglit line, the water 
which runs out of the fuperior jar is caught by that which is 
immediately below it, yet ftill there is a lofs ; and, befides 
this inconvenience, the whole quantity is raifed higher than 
the upper refervoir, at leafl by the diameter of the fprocket- 
wheel, becaufe it is only in their defcent that the jars are 

The fcreiu of Archimedes is a machine on a principle very 
clofely allied to the horn-wheel ; but the curved channels 
are wrapped fpiralwife round an axis, which is placed on an 
inchned pofition, with the lower end immerfed in the water 
which is to be raifed, and the upper end placed over the 
edge of the refervoir into which the water is to be delivered. 
When this cylinder is turned roUnd, it will take water up 
in its fpiral channel, and raife it gradually to the elevated 
end, and difcharge it into the refervoir. (See Screw.) 
Although this machine is fimple in its general manner of 
operation, its theory is attended with fome difficulties. 

If we conceive that a flexible tube is rolled regularly 
about a cylinder, from one end to another, this tube or 
canal will form a fcrew or fpiral, of wl»ich we fuppofe the 
intervals of the fpires or threads to be equal to one another. 
Suppofe this cyhnder placed with its axis in a vertical pofi- 
tion, if we put in at the upper end of the fpiral tube a fmall 
ball of heavy matter, which may move freely, it is certain 
that it will follow all the turnings of the fcrew from the top 
to the bottom of the cylinder, defcending always as it would 
have done, had it fallen in a right line along the axis of the 
cylinder ; only it will occupy more time in running through 
the fpiral. 

If we fuppofe the cyhnder placed with its axis horizon- 
tally, and we again put the ball into one openino- of the 
canal, it will defcend, following the direAion of the firft 
demi-fpire, until it arrives at the loweil point in this portion 
of the tube, and then it will Hop : for the weight of the 
ball has no other tendency than to make it defcend in the 
demi-fpire. The obhque pofition of the tube, with refpeft 
to the horizon, caufes the ball, in defcending, to advance 
from that extremity of the cylinder whence it commenced 
Us motion to the other extremity. When the ball is ar- 
rived at the bottom of the firft demi-fpire, if we caufe the 
cylinder to turn on its axis, without changing the pofition 



o( that axiJ, and in fuch manner that the loweft point of the 
demi-fpire on which the ball prefTes becomes elevated, then 
the ball falls necefTarily from this point upon that which 
fucceeds, and becomes loweft ; and as this fecond point is 
more advanced towards the fecond extremity of the cylinder 
than the former one, the ball will be advanced towards that 
extremity by this new defcent, and fo on, that it will at 
length arrive at the fecond extremity. Moreover, the ball, 
by conftantly following its tendency to defcend, has ad- 
Tanced through a right line, parallel and equal to the axis 
of the cyhnder ; and this diftance is horizontal, becaufe the 
fides of the cyhnder were placed horizontally. 

But fuppofe the cyhnder had been placed oblique to the 
horizon, and turned on its axis continually in the fame di- 
reftion, it is eafy to fee that the ball will move from the 
lower end of the fpiral tube towards the upper end, al- 
though it is aftuated folely by gravity, for this caufes it to 
occupy the loweft point of the firft demi-fpire ; and when it 
is abandoned by this point, as it is elevated by the rotation, 
and will roll by its weight upon that point which has taken 
its place, this fucceeding point is further advanced towards 
the elevated extremity of the cylinder than that which the 
bdl occupied juft before ; coiifequently the ball, while fol- 
lowing its tendency to defcend, will be always more and 
more elevated, by virtue of the rotation of the cyhnder. 
Thus it will, after a certain number of turns, be advanced 
from the lower extremity to the upper, or through the 
whole length of the fpiral; but it will only be raifed 
through the vertical height, determined by the obhquity of 
the poCtion of the cylinder. 

Inftead of the ball, let us now confider water as entering 
by the lower extremity of the fpiral canal, when immerfed 
in a refervoir. This water defcends at firft in the canal 
folely by its gravity ; but the cyhnder being turned, the 
water moves on in the canal to occupy the loweft place, 
and thus, by the continual rotation, is made to advance 
further and further in the fpiral, till at length it is raifed to 
the upper extremity of the fpiral, where it is expelled. 
There is, however, an efletitial difference between the water 
and the ball ; for the water, by reafon of its fluidity, will 
adapt itfclf to the form of the fpiral, and, after having de- 
fccnded by its hcavinefs to the loweft point of the demi- 
fpire, will rife up on the contrary fide to the original level ; 
on which account, more than half one of the fpires may be 
filled with the fluid. 

The moft fimple method of tracing a fcrew or a helix 
upon a cyhnder is well known to be this : — Take the hoight 
or length of a cylinder for the perpendicular leg of a right- 
angled triangle, and make the bafe or horizontal leg equal 
to as many times the circumference of the cylinder as the 
fcrew is to make convolutions about the cyhnder iifelf ; 
then draw the hypothenufe to complete the triangle. Sup- 
pofe this triangle to be enveloped about the furf^ce of the 
foUd cylinder, the perpendicular leg being made to lie 
parallel to the axis of the cylinder, and the horizontal leg 
or bafe to fold upon the circumference of the cylinder, even 
with its bafe ; then the hypothenufe or Hoping fide of the 
triangle will form the contour of the fcrew. If a tube be 
formed according to the direftion of this fpiral, and a fmall 
ball put into it when the cyhnder is placed upright, the 
ball would roll to the bottom with the fame velocity, and 
the fame force, as it would have dcfcended upon a plane 
furface, inchned in the fame degree as the hypothenufe of 
the triangle which we have fuppofed, when the bafe thereof 
is horizontal. But fuppofe the cylinder be inchned in fnch 
degree, that the hypotlienufe of the faid triangle would be 
horizontal inflead of the bafe, aa the angle which the 

threads of the fcrew make conftantly with the bafe of the 
cylinder is juft equal to that inclination, , the threads at 
their point of fmallcft inclination will be parallel to the ho- 
rizon ; fo that tiiere being nothing to occafion the ball to 
roll towards either end, it will remain immoveable, fup- 
pofing the cyhnder to be at reft ; but if the cyhnder be 
turned on its axis in one direftion, the ball (abftrafting 
from friftion) will move the contrary way, in conformity 
with the firft law of motion. The inclination which we 
have juft afhgned is the leaft we can give, fo that the ball 
fliall not defcend of itfelf ; but if we augment this inclina- 
tion, then, by turning the cylinder, the ball will always have 
a defcent on one fide, and will in confequence roll towards 
the elevated end of the fame, and will mount by defcending. 
The reafon is very fimple : the plane which carries it makes 
it rife more, in confequence of the rofatory motion, than it 
defcends by \'irtue of the force of gravity. It is obvious, 
from what has been remarked, that this fcrew can never 
raife water, when the angle which the central line of the 
fpiral makes with the bate of the cylinder is larger than 
the angle which the bafe of the cylinder makes with the 

The ratio of the weight of the ball to the force which is 
necelTary to make it rife by turning the fcrew, is as the ver- 
tical fpace through which the weight is raifed to the fpace 
pafTed through by the power in moving it. Suppofe the 
moving force afts at the circumference of the cylinder, the 
fpace pafTed over by that force will be equal to as many 
times the circumference of the cylinder as the number ot 
convolutions of the helix. Let the diameter of the cylin- 
der be 14 inches, the vertical altitude of the upper end of 
the cylinder above the lower end 12 feet, or 144 inches, and 
12 convolutions of the fpiral : let the cylinder be fo placed, 
that the inclination of the axis is greater than the inclination 
of the fpiral to the axis, and let the weight to be raifed be 
a 48 lb. ball. Tlie circumference of the cylinder will be 
nearly 44 inches, and the 12 turns equal to 12 x 44 = 
528 inches, for the fpace the power muft move through. 
Hence we have 528 inches : 144 inches :: 48 lbs. : 135- lbs. ; 
the meafure of the requifite force to be applied at the fur- 
face of the cylinder. If the moving force dcfcribes a circle 
whofe diameter is tlirce times that of the cyhnder, or afts 
at a winch whofe diftance from the axis of motion is 21 
inches, that force will then be reduced to j of i jj- or 4I lbs. 
which is lefs than one-tenth of the weight of the ball. In 
this invefligation, no notice is taken of the friftion upon the 
pivots, or of the effefts of the air included in the fpiral : 
yet if the fpiral had been folded upon a cone inftead of a 
cylinder, or if it had been formed of a flexible tube of va- 
rynig diameter, thefe effefts would have been important : 
fome of them are confidered in our account of the fpiral 

The Archimedes' fcrew is a machine fo frequently em- 
ployed in hydrauhc architefture, as to deferve particular di- 
reftions for conflrufting it. The fimple pipe wrapped 
round a cylinder will not afford any confiderable fupply of 
water, and therefore a hollow barrel muft be made with one 
or two fpiral partitions running in it, like the fpiral flair 
cafes ufed in church ftceples. 

Vitruvius has given minute direftions for the conftruftion 
of the water-fcrew, and Mr. Smeaton's direftions, which 
are very fimilar, are as follow : — For a fcrew of 18 inches 
diameter, ufe a folid cylinder of fix inches diameter as an 
axis, upon the furface of which cut a double helix, form- 
ing two feparate grooves round the axis of about three- 
quarters of an inch wide and deep, fo that the grooves in 
going once round will advance about fixtcen inches, and in 



confequenoe the two grooves will be eight inches apart from 
middle to middle, meafuring parallel to the length of the 
cylinder. Into thcfe grooves drive and faften pieces of 
board, fo as to form radii or feftors of a circle of eighteen 
inches and a half diameter, and fo moulded as to be a little 
upon the twift, to anfwer the different inclinations of the 
hehx, at the different dillances from the centre. Thefe 
pieces being jointed together, and to the axis, fo as to fill 
the whole groove from one end of the axis to the other, 
form a double fcrew ; then apply narrow boards longitu- 
dinall)', reaching from one end of the fcrew to the other. 
The boards fhould be about four inches broad, and formed 
^ concave withinfide, anfwerable to a circle of eighteen inches 
diameter. Thefe boards are marked one by one at the 
places where they touch the fpiral boards, and are then 
grooved about a quarter of an inch, to admit the ends of 
the radius pieces which form the fcrew. When all the boards 
are put together they form a cylinder of eighteen inches 
diameter, which is hooped on the outfide, in the manner of 
a tub or caflt ; and in order that the hoops may properly 
drive on the outfide, at the fame time that the infide forms a 
complete cylinder, the longitudinal pieces are made rather 
thicker in the middle than at the ends. 

Archimedes' fcrew may be ufed for other purpofes than 
raifing of water. It might be adapted with advantage in 
raifing cannon-balls from a (hip to a wharf, and with the 
addition of a bevel-wheel or two and their pinions, might 
be worked either by men or horfes. Sometimes Archi- 
medes' fcrew inflead of being worked by men at a winch, 
is turned by means of float-boards fixed on the circum- 
ference of a wheel placed at its lower end, upon which a 
ftream of water afts. If the water has a moderate fall, it 
will have fufficient efficacy to turn two fcrews, one above 
another. The top of the lower fcrew and the bottom of 
the upper fcrew may aft one upon the other, by means of a 
wheel upon each, with an equal number of teeth taking 
into each other. In this cafe the upper fcrew will turn in a 
contrary direftion from the lower, and confequenlly the 
fpiral lube mufl be wound about the cyhnder in an oppofite 
direftion. A folid wheel, or a light wheel with a heavy 
rim, turning upon the middle of the fcrew as an axis, will 
operate like a fly, and in fome cafes be very ufeful. 

Mr. Smeaton made a machine to raife water by an Archi- 
n\edes' fcrew for the royal gardens at Kew, which was on 
a large fcale. The fcrew was twenty-four feet long, two 
feet fix inches in diameter, and raifed the water perpendicu- 
larly fourteen feet nine inches. The central cylinder, or 
(haft of the fcrew, was ten inches diameter ; the diftance be- 
tween the threads, including the thicknefs of the helix, was 
twelve inches and a half ; and as there were two fpiral paf- 
fages, each fpiral advanced twenty-five inches along the cy- 
linder at every turn ; each fpiral contained twenty-feven 
quarts at every turn, the fcrew therefore gave out fifty-four 
quarts at every turn which it made. 

This fcrew was turned by means of a trundle or pinion 
from a horfe-wheel, with the intervention of two moveable 
joints, to change the direftion of the axis from the hori- 
zontal to the direftion of the axis of the fcrew, which was 
inclined at an angle of about thirty-eight degrees to the 
horizon. The diameter of the horfe-track was twenty- 
five feet, half of which was the length of the effeftive 
lever upon which the horfes afted. The great cog-wheel 
on the axis of the levers was fourteen feet diameter, with 
144 cogs, and the trundle which it turned twenty -three 
cogs, fo that the fcrew made about fix turns for one of the 

This machine was worked by two light horfes, with very 

great eafe, and they made three turns ^r minute ; but if at 
all urged, could make the fcrew turn twenty turns per mi- 
nute, and at that rate of working raifed 300 hogfheads per 

The Water-fcrew, defcribed in our article Screw, does 
not differ from the fcrew of Archimedes in its principle, 
but as the fcrew turns round within a fixed barrel, the water 
is liable to leak back in part. 

Drawing Water by Buckets The methods which we have 

hitherto defcribed are only adapted to raife water to fmall 
elevations ; but by means of buckets, water may be drawn 
from very great depths. The moft fimple cafe is that of a 
man with a bucket or other veffel in his hand, (looping down 
to lower the empty bucket into a pond, as low as he can 
reash, and drawing it up fuU of water. 

The firft improvement which would occur would be to 
fufpend the bucket by a rope, and draw it up by means of a 
long lever, or otherwife, if the depth was greater, by con- 
tinuing the rope over a pulley, fo that the man could eafily 
draw the end of it ; and this would be farther improved 
when two buckets were fufpended at the oppofite ends of 
the rope or chain, fo that one being drawn up full of water 
an empty one would be let down at the fame time. This 
method is applicable to the deepeft well, and is very effec- 
tive. The addition of a windlafs and crank would be a 
fucceffive improvement, and could be made to aft either 
fingly, to draw up one bucket, or double, to let down an 
empty bucket at the fame time it drew up another loaded 
with water. 

The drawing up of a bucket by a rope and pulley is 
fo fimple and obvious as to need no explanation. The 
bucket fhould be of fuch a fize that it will not weigh above 
twenty-fix pounds, and will therefore contain nearly half a 
cubic foot of water. For although a man could with eafe 
raife a much greater weight, yet he would be unable to 
draw it up fo quickly, or to work at it throughout the 
day ; and what he would gain by the increafed quantity of 
witer, he would lofe in the time which it would require to 
draw up the bucket, and in the time he would require to 
reft himfelf from his fatigue. If the rope is condufted ho- 
rizontally, and the man takes it over his fhoulder and walks 
along the ground, his force will be applied in a much more 
effeftive manner than by fimply hading the rope over a pul- 
ley ; and a horfe may be apphed in the fame manner with a 
larger bucket, and there is perhaps no better mode of ap- 
plying the force of a horfe for a deep well. The bucket 
fhould not in this cafe weigh above a hundred and twenty 
pounds, or it muft not contain above two cubic feet to 
enable the horfe to draw it with that velocity which is moft 
natural to him. 

When a v?indlafs is employed to wind up the rope, the 
winch or crank, which is applied to the axis of it, can be 
made much larger than the radius of the windlafs, and in 
confequence the power may be increafed fo much that a 
larger bucket may be drawn, which is fome advantage, be- 
caufe lefs time will be loft in flopping to fill and empty the 
bucket, otherwife nothing is gained in drawing up a large 
bucket, becaufe it muft move (lower in proportion to its in- 
creafed weight ; but in all cafes the length of the handle 
(hould be about fourteen or fixteen inches, to enable a man 
to turn it with eafe, and the weight of the bucket muft be 
fo adapted to the fize of the windlafs, that the power re- 
quired at the handle will not be above thirty pounds or even 
twenty-five pounds, if a man is to work continually for fix 
or eight hours in a day. For example, fuppofe the bucket 
is about forty-fix pounds weight, and the handle fixteen 
inches long, then as 46 is to 25, fo is 16 to 8|- nearly ; from 
F which 



which dcduft half the thicknefs of the rope, and it leaves 
the proper radius for the roller or windlafs. A rope of the 
proper fize for this purpofe will be about two inches and 
a half in circumference, or rather more than three-quarters 
of an inch in diameter ; hence the diameter of the barrel 
will be 1 6 J. If a fly-wheel is applied to the axis, it will 
be an advantage to equalize the force which the man ap- 
plies, becaufe fome pofitions of a crank or handle are lefs 
favourable than others for the exertion of a man's ftrength. 
It is moil advantageous to employ two buckets, and as the 
rope for one unwinds whilll the other winds up, the weight 
of the two buckets balance each other, and the man has only 
the weight of the water to draw up. 

Bucket-Machines for deep IVells .—Vfhen a machine to 
draw water by buckets is made on a larger fcale, the windlafs 
is placed perpendicularly, and levers applied to it at the lower 
end, which may be aftuated either by men, or by horfes 
walking round in a circle on the ground, and drawing or 
puihlng the end of the lever ; in this way a powerful ma- 
chine may be made, and if the depth is very confiderable, it 
is a very good method. Many methods have been propofed 
to make the buckets fill themfelves when at the bottom of 
the well, and empty when at the top : the beft is to fufpend 
the bucket in an iron loop or bow, hke the handle of a pail, 
but tliis (hould be made fo long, that the pins on which the 
calk or bucket bangs, fliall be but little above the centre of 
gravity of the bucket when loaded with water ; in confe- 
quence, when the bucket is drawn up to the top, one edge 
of it is caught by a hook fixed on the edge of the ciftern 
into which the water is to be delivered, and the bucket ftiU 
continuing to be drawn up whilft the hook detains one edge, 
the bucket is thereby overturned, and its contents difcharged 
into the rcfervoir. It is requifite for this plan, that the 
bucket be made, by fome contrivance, to prefent_ itfelf 
always in the fame dircftion to the hook, fo that it will be 
feized and overturned tliereby: one method is to fix upright 
pieces of wood or iron in the well on each fide of the bucket, 
and the pivots on which the bucket is poifed projeA on 
each fide beyond the iron loop on which the bucket hangs, 
and enter into grooves formed in thefe piece?, fo as to be 
guided in the afcent and defcent of the bucket. Another 
method is to make the rope of the bucket double for fome 
feet immediately above the bucket, that is, the rope divides 
into two ends, each of which is made faft to the oppofite 
fide of the iron loop in which the bucket is fufpendcd : the 
rope is made to pafs through a narrow opening in a piece of 
plank, which will admit the double rope to pafs freely, pro- 
Tided the bucket comes up in tiie required pofilion ; but if 
it does not, then the forked rope will be adled upon by the 
fides of this narrow opening in fuch manner, as to turn the 
bucket round to the required pofition. 

To make the bucket fill readily at the bottom of the well, 
a fimple valve is made in the bottom, which opens upwards 
and admits the water, but ftiuts when tlie bucket is drawn 
up out of the water. In the Tranfaftions of the Society of 
Arts, vol. xii. is a defcription of a machine by Mr. Ruirel, 
in which the bucket, when it is drawn up to the top of the 
well, a£ts upon a lever, and caufes a moveable trough to run 
acrofs the well beneath the bucket ; and then as the bucket 
rifes higher, a trigger, which belongs to the valve in the 
bottom of the bucket, is intercepted by a fixed piece of 
wood, fo as to open the valve, and the water runs out of the 
bucket into the moveable trough which conveys it into the 
refervoir : when the bucket begins to defcend, it allows the 
levers to return, and the moveable trough retreats from 
beneath the bucket, and allows it to defcend again into the 
well to bring up a frcfh charge. The 'moveable trough is made 

to run backwards or forwards over the mouth of the well, 
by means of wheels or rollers, on which it is fupported, and 
thefe wheels run upon pieces of wood laid acrofs the well. 

Indian Method of dra'wing IVater by a leathern Bucket. — 
Dp. Roxburgh of Calcutta has given us a defcription of a 
method of raifing a large quantity of water from a deep 
well by means of one or two buffaloes or bullocks, which 
is in conunon ufe in many parts of Hindoollan, where the 
wells are too deep for the lever. A pulley is ereAed over 
the well to receive a rope, which the animals draw by walk- 
ing along an horizontal path in order to elevate a large 
bucket, and they return towards the well to lower it down : 
the bucket is made of leather, like a long funnel, extended 
at the top or mouth by a fquare frame of wood, or by a 
hoop, and the lower end terminates in a fmall open tube, 
which is flexible, and can be turned up ; in which cafe, if the 
orifice of the tube is kept as high or higher than the mouth 
of the bucket, no water can efcape through the tube, it is 
in this condition that the bucket is drawn up full of water : 
the end of the tube has a cord fattened to it, which is con- 
dufted over a roller fixed on the edge of the trough into 
which it is defired to deliver the water, and which trough 
rauil be at leaft the length of the bucket beneath the great 
pulley that is fixed over the well. The oppofite end or the 
cord is tied to the great rope near the point where the 
buffaloes draw, and the cord is of fuch length as to hold 
the orifice of the tube rather above the mouth of the 
bucket, until the tube is drawn up to the roller. When tha 
cord draws the tube over the roller, and leads its end into 
the trough as the bucket continues to be drawn up, it is 
raifcd above the level of the trough, by which means the 
whole of the water will make its efcape through the orifice 
of the tube into the trough : when the bucket is let down 
again, the flexible tube returns over the roller, and the cord 
holds up its orifice above the top of the bucket. 

Dcfaguliers, in the fecond volume of Experimental 
Philofophy, defcribes a very fimple contrivance to raife 
water by a bucket ; which is this, to one end of a rope is 
fixed a large bucket, having a valve in its bottom opening 
upwards ; to the other end of the fame rope is fallened a 
fquare board, fometliing like the fcale-board of a balance, 
but large enough for a man to Hand upright in it ; the cord 
is made to pafs over two pulleys, each of about fifteen inches 
diameter, and lixcd in fuch manner, that as the bucket 
defcends, the fcale afcends with equal velocity, and vict 
•verfd. The fcale is made to run freely between four ver- 
tical guide rods, palfing through holes at its four corners, 
and when the bucket is lowered down into the lower water- 
ciftcrn in order to fill with water, the fcale ftands nearly 
level with the horizontal plane of the upper rpfer\'oir to 
which the water is to be raifed. When the bucket is full, 
a man fteps into the fcale, and his weight, together with 
that of the frame, exceeding the weight of the veffel and its 
contained water, will give an afcending motion to the 
bucket, and caufes the valve in its bottom to dole. When 
the bucket is raifod to the proper height, a hook which is 
fixed at the edge of the upper refervoir catches into a hafp 
at the fide of the bucket, and turns it over, to caufe it to 
empty its water into the upper ciftern, or into a trough, 
which conveys it where it is required : at this time the man 
and the fcale have arrived at a platform, which prevents 
their further dofcent, and the man muft remain in the fcale 
till he finds the bucket above is empty, when he fteps from 
the fcale, and runs up a flight of^ (tairs t6 the place from 
which he dcfcended : the bucket in the mean while, being 
fomewhat heavier than the fcale, defcends again to the w.itcr, 
and raifes the frame to it« original pofition ; thus the work 


is contiflued, the man being at reft during its defcent, and 
labouring in the afcent. 

Defaguliers employed in this kind of work a tavern- 
drawer, who had been ufed to run up and down (lairs ; he 
weighed 160 pounds, and was defired to go up and down 
39 fteps of 65 inches each (in all about 21 feet) at the fame 
rate he would go up and down all day. He went up and 
down twice in a minute, fo that allowing the bucket, with a 
quarter of a hogfhead of water in it, to weigh 140 pounds, 
he is able to raife it up througli 2 1 feet twice |in a minute, 
which is equivalent to the whole hogfhead raifed 10^ feet in 
a minute, and rather exceeds what Defaguliers affigned as 
a maximum of human exertion ; from experiments made with 
a mercurial pump. He recommends that the man in the fcale 
ihould weigh one-fifth or one-fixth more than the weight of 
the water in the bucket, in order to give him a prepon- 
derance to bring up the bucket with a proper velocity. 

Balance Buciets. — This is an ingenious contrivance for 
raifing water by the power of a fmall fall of water : fnppofe 
a wooden lever twenty feet long, poifed upon a centre at 
five feet from one end, one arm will then be five feet long, 
and the other fifteen, or three times. At the extremity of 
the long arm a fmall bucket is fixed, and at the extremity of 
the fhort arm another bucket, which is rather more than 
three times as great in capacity : the lever is fo poifed, that it 
will place itfelf in an horizontal pofition when both the 
buckets are empty ; but fuppofe that in this fituation a fmall 
fpout of water runs into each bucket, when they become 
both filled, the larger bucket at the end of the ihort arm 
will overweigh the fmaller one, becaufe it holds more than 
three times as much water; in confequence, the larger bucket 
will defcend and move the lever into a perpendicular fitua- 
tion, by which means the fmall bucket is raifed fifteen feet 
above the level of the fpout at which it received the water, 
whilil the great bucket has defcended five feet beneath its 
fource of fupply. Both the buckets are fufpended to the 
ends of the lever on pivots, fo that they can readily be 
turned over to difcharge their contents ; this takes place 
when the lever arrives near its vertical pofition : the fmall 
bucket is caught by a hook, and overturned into the elevated 
trough which is to receive the water, and immediately the 
lower bucket is emptied by fimilar means. The long end 
of the lever is now the heavieft, and in confequence the lever 
returns to its horizontal pofition, in which it remains until 
the buckets are both full, and then it makes another ftroke. 
A fimple contrivance is applied to flop the running of the 
fpout of water during the time that the lever is in motion, 
to prevent waile of the water. 

The hfmg and gaining Buckets is a fimilar machine to the 
preceding, but admits of raifiiig the water to a greater 
height, becaufe chains and wheel-work are employed inftead 
of a lever. This machine will raife water fufficient to ferve 
a gentleman's feat, with an overplus for fountains, fifh-ponds, 
&c. A machine of this kind can be erefted wherever 
there is a fpring affording a fmall fupply of water, and 
having even fo fmall a fall as ten feet. It is pofTible, by 
this invention, with the lofs of part of the water, to raife the 
reft, to fupply a houfe, or any placewhereit is required; but, 
of courfe, it miift be in a lefs quantity than the fall of water 
which is to aftuate the machine, nearly in the fame propor- 
tion as the place to which the water is to be raifed is higher 
than the fall of the fpring. For example, the fall of one hogf- 
head through ten feet will raife about one-fixth of a hogfhead 
to the height of forty feet. This machine had been con- 
ceived by Schottus a great many years ago, and he gave a 
draught of it. It is defcribed in Leopold's Theatrum 
Slachinarum Hydraulicarum, 1720 ; but it was never 

put in execution to any good purpofe in England, till 
Mr. George Greaves, a carpenter, erefted an engine upon 
this principle, about 1730, for fir John Cliefter, baronet, at 
his feat at Chickley, in Buckinghamfhire ; a Hcetch of 
which is given at Jig. 13, Plate Water-Worls. A fmall 
fpring of water, fupplying four gallons per minute, is con- 
veyed feventy-two yards, by a gutter,' into a ciflern N, 
containing about twelve gallons. This water has a de- 
fcent to the other ciftern at R, ten feet below X ; from 
the latter, the wafte is conveyed off along H, by a drain or 
fewer. The defcent of part of the water through this ten 
feet is the motive force to work the machine. A, B, are two 
copper pans, or buckets, of unequal weights and fizes, fuf- 
pended by chains, which alternately wind off, and on the 
two multiplying-wheels Y and Z, whereof the wheel Y is 
fmaller in diameter, and Z larger, in proportion to the dif- 
ferent lifts each bucket is defigned to perform. A houfe 
is built over the well or ciftern, with three floors, for the 
conveiiiency of fixing the parts of the engine. On the 
uppermoft floor is fixed a frame of timber 2 2, in which the 
moving parts are fupported, as is fhewn, (part being broken 
off" in the figure, to explain the work ) : acrofs this frame 
lies an horizontal axis G, three feet and a half long, moving 
on two gudgeons in braffes. Upon this axis are framed 
three wheels ; firft, the fmall wheel Y, which is two feet 
diameter, and ftirouded, or made with a raifed rim at each 
fide : the edge of the wheel is five inches broad, and fliod 
with iron. Upon the wheel Y is fixed a chain, made very 
flat and flexible, which, after it has wrapped once round 
the wheel, is then made double, that it may lie on each 
fide of the edge part, the double parts having a fufficient 
opening between them to admit the fingle part, and this pre- 
vents fretting or galling, and keeps the chain exadlly per- 
pendicular : from the extremity of the double part is hung 
a long rod of iron, at the bottom of which the great bucket 
A is fixed. The largeft wheel Z on the axis is fix feet 
diameter, and one inch and a half broad on the face, which 
is alfo flirouded : this wheel is not circular, but fpiraled 
two inches, both in the fole and in the fhrouds ; fo that its 
radius at the leaft part is two inches lefs than three feet. 
Upon the large wheel Z is fixed a fmaller chain, to fuf- 
pend the bucket B : it is made like the former, and fo 
arranged, that when the wheel Z has made one revolution 
from left to right, the fpiral fole will take up a certain 
length of the chain. After this length, the lower or re- 
maining part of the chain has crofs-bars fixed to it, at equal 
diftances, which fall upon the edges of the fhrouds into 
notches plated with iron: by this means, and by the help 
of the fpiral, this part of the chain is not only prevented 
from riding upon the other, but helps to equiponderate the 
increafe of weight of the other chain of the bucket A. 
A third wheel r, three feet ten inches diameter, is fixed 
on the axis G, between the other two wheels : it is (hrouded 
like the others, and is fpiraled three-fourths of an inch ; it 
receives a rope, the lower end of which goes about a wheel 
d, of two feet diameter, to which that end is fixed, and on 
the axis, d, of this wheel is another, /, one foot diameter, 
and to this is faftened a rope, which goes down upon the 
quadrant ab, which carries a Aiding weight in a box at the 
extremity of the arm Q ; the quadrant a moves on the 
axis b, and the rope defcending from the wheel t, is guided 
between iron plates, upon the circumference of the qua- 
drant. The box, at the end of the arm Q, contains a Aiding 
lead weight, to counter-balance the weight of the chains, 
by keeping an exaft equilibrium in every pofition of the 
machine. Befide* the aftion of the quadrant, the motion is 
regulated by wheel-work, hke that of a jack ; thus, upon 
F 2 one 


one end of the axis G, is a ftrong iron wheel M, giving mo- 
tion to a pinion m, and by means of a wheel and worm n and 
0, to a fly P, which regulates the motion of the engine, and 
prevents any improper acceleration from the unwinding 
of the chains. The fmall bucket B is made of copper, 
about five gallons in capacity ; it has a valve in the bottom, 
by which the bucket will be filled when it defcends into the 
water of the ciftern N. The bucket is fufpended in an 
iron hnk, or handle, upon two pivots, fo that it can be 
very eafily turned over upon them. This happens when it 
is drawn up to F, the edge of the bucket catching a hook 
which overturns it, and difcharges the contents into the 
trough W, at an elevation of thirty feet above X, and 
whence it is conveyed by pipes wherever it is wanted. 
The great bucket A is likewife made of copper, and 
contains about fifteen gallons when drawn up to the poli- 
tion A : it is filled with water from a valve, or fluice, in the 
fide of the ciftern N, which is then opened by a bent lever, 
whereof the end projefts, fo that the bucket will lift it up. 
In the bottom of tlie bucket is a fpindle-valve, which is 
opened when the bucket has dcfcended to R, by the end of 
its fpindle refting on the bottom of the well. Iron rods 
are fixed vertically to guide both the buckets, which have 
ears with brafs rollers in them, and inclofe three fides of 
each, which is fquare, and they are tluis caufed to afcend 
and defcend in a perpendicular line, and no other. 

The operation of the machine is as follows: — When the 
buckets are empty, they are ftopped, as fhewn in the figure 
on a level with the fpring at X, whence they are both filled 
with water at the fame time, in the manner juft defcribed. 

The greater of the two A, being the heavie--, when full 
preponderates, and defcends ten feet from C and D, and 
the IcfTcr B, depending from the fame axis, is at the fame 
time weighed up or raifed from B to F thirty feet. 

Here, by catching the hook F, the fmall bucket dif- 
charges its water into the trougli W, and thus fuddenly 
lofing weight, it lets the great bucket down an inch lower, 
and the valve in the bottom is opened, fo as to let out its 
water, which runs wafte by the drain below at H. The 
bucket B being then empty, is fo adjufted as to overweigh, 
and defcending fteadily as it rofe, betwixt the guiding-rods, 
it brings or weighs up A to its former level at X, where 
both being again rcplenifhed from the fpring, they thence 
proceed as before. And thus will they continue conftantly 
moving, (merely by the circumftantial difference of water 
and weight, and without any other afliftance than that of 
fometimcs giving the iron-work a httle oil,) fo long as the 
materials (hall laft, or the fpring fupply water. 

The lleadinefs of the motion is, in part, regulated by the 
fly P, which not only keeps the engine to an equal velo- 
city, but by its running forwards, after the buckets are 
quite up or down, holds them fteady till they are completely 
filled or emptied, and prevents them recoihng back too 
foon. In order to counterbalance the weight of the chains 
in every pofition, the wheels r, </, and /, are fo calculated, 
that during the whole performance up and down, they let 
the quadrant a move no more than one-fourth of a circle ; 
by which contrivance, as more or Icfs of the chains which 
fufpend the buckets come to be wound off thoir refpeftivc 
wheels Y and Z, this weight gradually increafes its aftion 
as a counterbalance, and fo continues the motion equable 
aad eafy io all its parts. The fpiraling of the wheels Y 
and Z help, in fome meafure, to regulate the weight of the 
chaina in every pofition, as they aft in winding on and off 
the wheels ; but the quadrant a b, and lever with the 
weight Q, complete the equilibrium, by afting with the 
greatcft force, becaufc the lever is in the horizontal pofition 

when the chain of the great bucket A is all down, and 
weighing upon the wheel, the weight Q then afts with its 
whole weight upon the wheel /, as that chain is drawn up, 
its afting weight is thereby diminilhed, and the lever of the 
weight Q is moving down towards its perpendicular, 
whereby the weight Q dimini(hes equally in its influence 
on the motion of the wheel r, until it hangs perpendicular, 
and its weight ceafes to aft ; but the fliding-weight then 
runs down in its box, to keep the rope tight, the Hiding- 
weight being attached to the end of the rope, and not to 
the lever. At the firft return, or re-afcent of the great 
bucket, the weight Q is drawn up to a (houlder, before 
any motion is given to the lever of the quadrant ; but 
whilft the long chain of the fmall bucket evolves from its 
wheel Z, the afting-weight of the quadrant is contioually 
increaCng, and at the fame time the other chain of the great 
bucket wrapping itfelf upon the wheel Y, its afting weight 
is decreafing. The lever of the quadrant rifing higher, 
brings the line of direftion of the weight Q farther from 
the centre of the quadrant, and fo lays a greater force or 
obftruftion to retard tlie wheel r, and continually keeps a 

This engine, at a flow motion, carries up one bucket full 
in five minutes ; but if the fpring ran double the quantity, 
it would go up twice in the fame time, and an engine of 
this kind may be made to raife one hog(head/>£r minute, or 
more, if required, the confumption of water is lefs tliau 
what is fpent by a water-wheel to raife an equal quantity 
of water to the fame height. 

The Endlefs Rope to raife IVater. — This is a moft fimple 
contrivance, and will raife up a fmall quantity of water from 
a very confiderable depth. A foft hemp or hair-rope, 
with the ends fpliced together, is fufpended over a large 
wheel, which is turned by a handle ; the rope muil liang 
down into the well, and reach fome depth into the water, and 
a fimilar wlieel may be placed beneath the furface of the water 
for the rope to pafs under ; but this is not neceffary when the 
length of the rope is fuch, that its own weight will make 
it apply clofe to the upper wheel. The upper part of the 
rope muft defcend ihrougli a tube, which is fixed in the 
bottom of the ciftern, or refervoir, to prevent the water 
running down with the rope ; the tube is of fucli fize as to 
fit the rope very nearly, but not to caufe any confiderable 
friftion. The rope is put in motion by turning the handle 
of the wheel, and the motion muft be in fuch a direftion, 
that the rope where it paffes through the tube in the ciftern 
fhall defcend. 

The confequence is, that the water in the well adheres 
to the rope, and furrounds it like a film, or covering of 
water ; but when the rope paffes over the wheel, fome of 
the water is thrown off by the centrifugal force, and falls 
into the refervoir, and that part of the water which efcapes 
the aftion of the wheel is feparated from the rope by the 
tube through which the rope paffes ; for it is to be obferved, 
that the film of water which furrounds the rope is put in 
motion, wliilft it is in the well, by the lateral adherence of 
the water to tlie rope, which motion being continually 
kept up, is fufficient to overcome the gravity of the water ; 
but if any body is prefented to the rope, fo as to refift the 
motion of the water, without obftrufting the motion of the 
rope, the water will fly off, and, lofing its motion, will obey 
the aftion of gravity, and f-iU down. 

The velocity with which the rope requires to be moved, 
will depend upon the depth from wliich the water is to be 
raifed. The length of that part of the rope which is im- 
merfed in the water is alfo of fome confequence, for it 
muft be fuch, that the rope will aft upon the ftill water 



which immediately furroimda it, until it has put that water 
in motion with nearly the fame rapidity as the rope, and 
then fuch portion of water will accompany the rope ; but 
tliis cannot take place without communicating a flower 
motion to a much larger quantity of water, which will alfo 
accompany the rope with a flower m.otion ; but being too 
far removed from the rope to have its motion accelerated, 
or even maintained, its velocity will continually decreafe, 
until it ceafes to afcend, and then it will begin to run back. 
But this is to be underltood only of that part of the water 
which is too far diftant from the rope to have its motion 
fully maintained by the lateral adlion of that water which 
is nearer to the rope, and which moves with nearly the fame 
velocity as the rope. If the rope is examined at the point 
wheie it rifes above the furface of the water, it will be 
found to be furrounded by a column of water which is of a 
confiderable fize at the bafe, but diminifhes as it rifes up- 
wards, fomevvhat in the form of a trumpet, fo that at a few 
feet in height it is but little larger than the rope. This 
column of water is compofed of feveral laminse, each moving 
with a different velocity : for initance, the interior part 
moves nearly as quick as the rope, the water which is more 
diftant from the rope moves flower, until there muft be a 
part in which the water remains immoveable, and all the 
water which is beyond this, and on the outfide of the 
column, runs downwards, and falls back into the well. On 
this account, the machine lofes a confiderable part of the 
power Wliich is aipplied to it without producing an adequate 

This machine was invented by the Scur Vera, in France. 
A machine was made by him with a wheel three feet dia- 
meter, and a hair-rope of half an inch diameter, the well was 
ninety-five feet deep. A man could turn the wheel fixty 
times ^fr minute, which gives a velocity of five hundred and 
fixty-five ieet per minute for the rope. It brought up fix 
gallons per minute, but was fevere labour for one man. 
When the wheel made fifty turns, and the rope moved four 
hundred and feventy-one feet per minute, the machine ftill 
raifed a confiderable quantity of water ; but if the motion 
was reduced to thirty turns, or two hundred and eighty-two 
feet per minute, it brought up fcarcely any water. A rope 
of hair is preferable to hemp, becaufe it is lefs fubjedl to 
decay ; and when a hemp-rope begins to rot, it commu- 
nicates a taint to the water. 

The Sucking-Pump lias a valve at the bottom of the bar- 
rel, and alfo another valve in the pifton, which is called a 
bucket, becaufe it brings up the water before it. This 
pump does not raife water when the bucket is let down, but 
only when it is drawn up, which is in fome cafes an incon- 
venience ; and another objeftion is, that it cannot raife 
water to a greater height than the place where the power is 
applied, becaufe there mull be an opening for the pump-rod 
to come out at, and the water would flow out at the fame 
opening, if it was raifed as high. This inconvenience is 
remedied by 

The Lift-Pump, which has a valve in the bucket, the fame 
as the fucking-pump, but it differs from it in the manner of 
communicating the force to the pifton or bucket : one way 
of effefting this is to make the barrel open at the lower end, 
and the rod from the bucket, inftead of being fixed to the 
upper fide of the bucket, is fixed to the lower fide, and 
comes out beneath the furface of the water in which the 
barrel is immerfed. Rods are jointed to this, and rife up pa- 
rallel to the barrel, in order to be attached to the lever by 
which the pump is to be worked : the fixed valve is placed 
at the top of the barrel above the bucket : this is the old- 
fafhioned lift -pump. 

The Lift-Pump luith a Slujing-box, called foinctimes a 
jack-head pump, is exa<ftly the fame as the fucking-pump, 
except that the top of the barrel is covered by a lid, which 
has a hole in the centre for the rod to pafs through : the 
rod is made very fmooth and true, and the hole is fo formed 
as to contain collars of leather, which fit clofe round the rod, 
and prevent the efcape of any water by the fide of the rod. 
The water mounts up a pipe which communicates fideways 
with the upper part of the barrel. 

Another form of hft-pump has been recently introduced, 
in which the pifton is folid, having no valve in it, and the rod 
pafles through a ftuffing-box or collar of leather in the top 
of the barrel, the bottom of the barrel being open. Two 
pipes are made to communicate fideways with the barrel at 
the upper part, one of which brings water from the well 
into the pump when the pifton defcends, and has a valve 
in it to prevent the return of the water ; the other pipe 
conveys the water away from the barrel when the pif- 
ton is drawn upwards, and this is likewife furniftied with a 
valve to prevent the return of the water. 

One advantage of this kind of pump is, that both valves 
are fituated in boxes near the top of the barrel, and can be 
examined and repaired at any time by taking off' the doors 
or covers of the boxes ; but in pumps where there is a valve 
at the bottom of the barrel, it fometimes happens that the 
valve fails, and requires to be repaired, when the water in the 
well ftands higher than the cover or door of entry to the 
valve : in this cafe, fome other means muft be ufed to reduce 
the water in the well, or elfe the pump muft be drawn up 
out of its place, which, in large works, is very difficult. 
Another advantage is, that the apertures of the valves may 
be made of any required dimcnfions to let the water pafs 
freely through them ; but when the water muft come up 
through a valve in the bucket or pifton, the paftage through 
the valve muft neceflarily be much fmaller than the barrel, to 
allow a proper lodgment all round for the valve and alfo 
for the leathers. 

The Force-Pump-^-This is made with a folid pifton, like 
the laft, but the barrel is open at the top, where the pifton-rod 
comes out. There is a valve at the bottom of the barrel to 
admit the water into it, and a pipe, which turns fideways 
out of the barrel at bottom, and has a valve to prevent the 
water returning into the barrel, to convey the water to what- 
ever place it is to be forced to. The force-pump raifes 
water only when the pifton is preflied down, whereas the 
Ilft-pumps and fucking-pumps raife the water when the 
buckets are drawn up. 

The Lift and Force-Pump of M. De la Hire. — This is the 
union of the two laft pumps in one, for both thefe pumps 
work with a folid pifton, and the barrel of the force-pump 
is open at top, and the barrel of the lift-pump is open at 
bottom ; hence the fame barrel and pifton may be made to 
ferve for both. This pump throws up water equally when 
the pifton-rod is drawn up or when it is forced down, and 
is moft proper for the double-afting fteam-enginc. It has 
the advantage of raifing twice the quantity of water that 
any of the other pumps will raife, and with the friftion of 
only one pifton ; alfo the valves admit of being made of fuf- 
ficient fize to allow the paftage of the water without any 
unneceffary refiftance. 

Force-Pump with a folid Plunger. — This was invented 
by fir Samuel Morland, and does not differ from the force- 
pump laft defcribed, except in the manner of fitting the 
pifton to the barrel. Inftead of the barrel being bored tridy 
cylindrical withinfide, and the pifton fitted into it fo as to flide 
up and down, and provided with leathers to make a clofe fit- 
ting, the pifton is made of a cylindrical form, and very nearly 


a3 large as the liollow barrel into vvliich it defcends, but it 
does not touch the infide of the barrel. To make the clofe 
fitting.the outfide furface of the cylindrical piftoii.or plunijer, 
as it is called, is made very true and fmooth ; and it is fur- 
rounded by a collar of leathers fixed at the top of the barrel, 
fo that no water can leak out of the barrel between the 
plunger and the leather collars ; at the fame time that the 
plunger can freely move up and down through the collars, 
and will thereby increafeor diminifh the capacity of the bar- 
rel, to produce the fame efFeft as if the pifton fitted clofe 
into the barrel. 

The principal circumllance to be attended to in this 
pump is the conftruftion of the collar of leathers. To re- 
tain thefe leathers in their places, the top of the barrel muft 
be made \nth a flaunch, and pierced with holes to receive 
fcrew-bolts. Upon this flaunch two rings of metal are ap- 
plied one over the other, with fimilar holes : the internal 
opening in the lowed ring is exaftly tlie fize of the plunger, 
and that of the upper one a little larger. Two rings of foft 
leather are cut out to correfpond with the metal rings, except 
that the central holes are rather fmaller than the plunger : 
to prepare the leather, it is fuaked in a mixture of oil and 
tallow for fome hours. One of thefe leather rings is laid 
on the pump-flaunch, and one of the metal rings placed above 
it ; the plunger is then thruft down through the leather, which 
turns the inner edg« of the leather ring downwards ; the 
other leather ring is then flipped on at the top of the plunger, 
and the fecond metal ring is put over it, and th'n the whole 
are (lid down to the metal ring ; by this the inner edge of 
the laft leather ring is turned upwarrls. 

The metal rings and leathers are now fixed on the flaunch 
by the fcrew-bolts ; and thus the leathern rings are ftrongly 
comprefTed between them, and make a clofe joint with the 
top of the barrel ; and as the holes through the leathers are 
fmaller than the plunger, they grafp the plunger fo clofely 
that no preffure can force the water through between them. 
The lower metal ringjuft allows the plunger to pafs through 
it, but without any play, fo that the turned-down edges of 
the lower leathern ring cannot come up between the plunger 
and the lower metal ring, but are lodged in a conical enlarge- 
ment, which is made round the inner edge of the upper 
part of the barrel ; and in like manner the turned-up edges 
of the upper leather are received in the hole of the upper 
metal ring, which liole is made larger than ttie plunger, to 
leave a fpace all round for thefe edges : it is on thefe trifling 
circumflanccs that the great tightnefs of the collar depends. 
To prevent the leathers from fhrinking by drought, there is 
ufually a little ciftern formed round the head of the pump, 
and kept full of water. 

This kind of pump is preferable to any other, where the 
prefTure to be overcome is very confiderable. The hydro- 
ftatic prefTes are conllruAed on this principle. See Press. 

P'lftoru or Buckets for Pumps. — A good pifton (hould be 
as tight as poflible, and fliould have as little friftion as is 
confiftent with this indifpenfible quality. The bucket of 
the common fucking-pump, when carefully executed, pof- 
fefles thefe properties in a high degree, and is the model for 
Other kinds of pump-buckets, or piftons, in which leather 
can be employed. This bucket is in the form of a truncated 
cone, with a hollow through the centre of it, which is half as 
large as the outfide, at the largeil part ; it is generally made 
of wood not liable to fplit, fuch as elm or beech, but in the 
beft kind of pumps is made of metal. The fmall or upper 
end of it is cut away at the fides, fo as to open into tlie 
hole through the centre of it, and form an arch, by whicli it 
is faftened to the iron rod or fpcar of the pump, and within 
the arch the valve or clack is fituated. The lower end of 

the conical part may be covered with a hoop of brafs, vfrhich 
fits the barrel of the pump very exaAly ; the bucket is alfo 
furrounded witli a ring or band of ftrong leather, faftened to 
the wood with nails, and firmly retained by the brafs hoop 
which is driven down on the bucket from the upper or the 
fmaller end of the cone, and binds the leather faft on the 
wood ; but the leather being wider than the brafs, the edge 
of the leather rifes upwards and furrounds the wood : this 
part of the leather is made to turn outwards, like a cup or 
hollow cone, which, at the upper end, is rather larger than 
the barrel, fo as to fpring againil the infide of the bar- 
rel when the bucket is put into it. The leather muft be of 
uniform thicknefs all round, fo as to fuffer equal compref- 
fion between tlie wood of the bucket and the working 
barrel, but this compreflion is very flight, bccaufe it is the 
upper edge of the cup which applies moft clofely to the 
barrel. The feam or joint of the two ends of the band of 
leather muft be tapered, and made to overlap and lie very 
clofe, without increafing the thicknefs, but not fewed or 
ftitched together, as that would occaCon bumps or inequa- 
lities, which would fpoil its tightnefs ; and no harm can 
refult from the want of fewing, becaufe the two edges will 
be fqueezed clofe together by the compreflion in the 
barrel ; nor is it by any means neceflary that this compreflion 
be great, for it occafions friftion, and caufes the leather to 
wear through very foon at the edge of the bucket, and it 
alfo wears the infide of the working barrel, which foon be- 
comes enlarged in that part which is continually pafled over 
by the pifton, while the mouth remains of its original dia- 
meter, and then it is impofllble to thruft in a pifton which 
(hall completely fill the worn part. A very moderate pref- 
fure is fufficient for rendering the pump perfeAIy tight, 
becaufe the prelTure of the water makes the leather cup ap- 
ply itfelf clofe to the barrel all round, and even adjuft itfelf 
to all its inequalities. Suppofe itrto touch the barrel in a 
ring of an inch broad all round, this is a trifle, and the fric- 
tion occafioned by it not worth regarding ; yet this fmall 
furface is fufficient to make the paDTage perfeftly imper- 
vious, even by the prelTure of a very high column of incum- 
bent water : for let this prelTure be ever fo great, the pref- 
fure by which the leather is forced againft the infide of the 
barrel will always exceed it, becaufe, in addition to the pref- 
fure of the water, the leather will always prefs againft the 
barrel by its own elafticity, the top of the cup of leather 
beinir made rather larger than the interior of the barrel. 

This method of applying leather piftons is found to be 
preferable to any other, becaufe if the leather is prelTtd 
againft the barrel by any other means than the force of the 
column of water, the prelTure will always be too great or 
too little. 

Pumps which are to raife hot water cannot be leathered, 
becaufe the leather would (hrivel up ; in this cafe, ftrong can- 
vas cloth is fometimes ufed inftead of leather ; but as this will 
not hold water pcrfeftly, fuch pumps are generally packed 
with hemp, in the fame manner as the pifton of fteam- 

Pump without Frifilon. — When the height to which the 
water is to be raifed is fmall, a pump may be conftrufted in 
which the pifton does not require to be fitted clofely into 
the barrel, nor are any leathers required. The barrel of thia 
pump muft be as long as the whole height to wiiich the 
water is to be raifed, and as much more as the length of the 
llroke of the pifton. The pifton is a fohd piect of wood, 
fitted to the barrel as clofely as it can be without aAually 
touching the infide, and may be cither fquarc or round, but 
a fquare trunk and a fquare beam of wood are beft, if the 
pump is made of wood. The pifton muft be a* long as the 



barrel, fo that when it is let down it will occupy the whole 
interior fpace of the barrel, except that fmall fpace which 
is left between the iufide of the barrel and the pilton, to 
avoid aftual contaft. The bottom of the barrel has a valve 
in it which opens upwards, and a pipe proceeds from the 
lower part to convey away the water to the refervoir into 
which it is to be raifed by the pump. This pipe is pro- 
vided with a valve, to prevent the return of any water 
which has paffed through it, but the greateft elevation of 
the water in the refervoir mud not be quite fo great as the 
top of the barrel. When this pump is fixed for work, the 
lower end of the barrel muft be immerfed in the water of 
the well at leaft as much as the whole length of the ftroke, 
fo that the lower end of the pifton will never rife above the 
furface of the water in the well, and upon this circumftance 
the adlion of the pump depends ; for when the pillon is 
drawn up, the water flows through the valve in the bottom 
by its gravity, and fills the fpace which is left by the draw- 
ing up of the pilton ; when the pifton defcends, it difplaces 
from the barrel all this water, and forces it up the fide-pipe 
into the refervoir. It is true that a fmall portion of water 
rifes in the fpace between the barrel and the piilon, but 
this fmall quantity cannot efcape, becaufe the top of the 
barrel rifes higher than the furface of the water in the re- 

Dr. Robinfon, who we believe firft defcribed this pump, 
obferves that it is free from all the difficulties which are 
experienced in common pumps, from want of being air- 
tight. Another is, that the quantity of water raifed is 
very nearly equal to the power expended ; for if there is 
any want of accuracy in the work, which occafions a dimi- 
nution of the quantity of water difcharged, it alfo makes an 
equal diminution in the force which is neceffary for pufliing 
down the plunger. The doftor mentions a machine, con- 
fifting of two fuch pumps, the piilons of which were fuf- 
pended from the arms of a long beam or lever, the upper 
fide of which was formed into a walk, with a rail on each 
fide. A man flood on one fide of tiie centre of the lever, 
until the pifton of the pump at that end funk to the bottom 
of its barrel, and of courfe the pilton of the pump on the 
oppofite fide of the centre was drawn up ; he then walked 
flowly up to the other end of the walk upon the beam or 
lever, the inclination being about twenty-five degrees at 
firft, but gradually diminiftied as he went along, and pafied 
on the oppofite fide of the centre of motion, fo as to change 
the load of the beam. By this means he made the pifton at 
the other end go to the bottom of its barrel, and lo on al- 
ternately, with the eafieft of all exertions, and what a man 
is moil fitted for by his ftrnfture. With this machine a 
feeble old man, weighing iic pounds, raifed 7 cubic feet 
of water ll'l feet high every minute, and continued work- 
ing eight or ten hours every day. A ftout young man, 
weighing nearly 135 pounds, raifed 83- cubic feet to the 
fame height ; and when he carried 30 pounds conveniently 
fiung about him, he raifed ()\ feet to this height, working 
ten hours a day, without greatly fatiguing himfelf. This 
exceeds Defaguliers' maximum of a hogftiead of water ten 
feet high in a minute, in the proportion of 9 to 7 nearly. 
This pump, is limited to very moderate heights, and in fuch 
fituations it is very effeftual. 

The mercurial pump is a fpecies of lift -pump, in which 
mercury is employed to make a clofe fitting between the 
pifton and the barrel, and thus avoid the friftion of leathers, 
and prevent lofs of water. 

This pump was originally invented by Mr. Jofhua Haf- 
kins, and was improved by Defaguhers, who defcribed it in 

the Philofophical Tranfadtioiis for 1722, N" 370. p. 5 ; 
and he has alfo given every detail of the conftruftion in his 
Experimental Philofophy, vol. ii. p. 491. 

In this pump the barrel is inverted, that is, it is open at 
the bottom, like the firft lift-pump which we have men- 
tioned ; and it has alfo two pipes communicating with the 
upper end of the barrel, one to bring up the water from 
the well, and the other to carry it up to the refervoir : each 
pipe is provided with its valve, to prevent the return of the 
water. The barrel muft. be made of iron, and as thin as is 
confiftent with the ftrength of the metal. The pifton is a 
cylindrical plug of wood, fitted to the barrel fo as to fill it, 
but not to touch the fides. This pifton is fixed perpendi- 
cularly in the centre of a hollow cylinder of iron, which is 
rather larger within than the outfide of the pump-barrel, fo 
tiiat an annular fpace is left all round between the folid 
pifton or plug and the infide of the cylinder, into which fpace 
the pump-barrel can enter, and will fill it very nearly. The 
annular fpace is then filled with mercury. This compound 
piece, confifting of the hollow cylinder, with the fmaller 
fohd cylinder within it, forms the pifton ; and to this the 
power which is to work the pump is applied by means of 
chains, which fufpend it from the (hort arms, fo that if the 
lever is moved, the pifton will rife up and down. When 
the pifton is applied in its place, and the inverted pump- 
barrel is received into the annular fpace between the folid 
and hollow cylinders, the mercury therein will make a clofe 
fitting between the folid pifton and the infide of the barrel, 
fo as to prevent any water pafTuig between them ; and the 
afcent and defcent of the pifton will produce an alternate 
contraftion and dilatation of the internal capacity of the 
working barrel, in the fame manner as a folid pifton would 
do, if it was clofely fitted to the infide of the barrel with 
leather ail round. 

As the water exerts a prefFure on the mercury, to force 
it out of the annular fpace in which it is lodged, the depth 
of the annular fpace and length of the barrel which defcends 
into it muft be adapted to the height to which the water is 
intended to be elevated ; fo that the column of mercury 
which it will contain, without raifing the mercury fo high as 
to run over the edge of the external cyhnder, Hiall always 
exceed one-thirteenth part of the lieight to which the water 
is to be elevated ; the weight of mercury being more than 
thirteen times the weight of an equal quantity of water. 

That there may be lefs mercury ufed, the pump-barrel 
fhould be made of plate-iron, turned on the outfide, and 
bored within ; the outer cylinder of the pifton ftiould be 
bored, and the inner one turned ; and if the work be well 
performed, eight or ten pounds of mercury will be fuffi- 
cient, though the bore of the barrel, or diameter of the 
column of water which is raifed, is fix inches. Lefs than 
fix pounds of mercury would fuffice, if there were two bar- 
rels, in order to keep a conftant ftream. This will very 
much lefTen the expence of mercury, which would otherwife 
be an objection againft this pump ; and by making the inner 
and outer cylinder of hard wood, as box, or lignum "vitit, the 
expence may ftill be reduced. But if the engine be very 
large, caft-iron bored will be proper for the outer cylinder, 
and caft-iron turned on the outfide for the inner cyhnder or 
plug, and hammered iron bored and turned for the middle 

There is an objeftion, which feems at firft to take off the 
intended advantage of this engine, •viz.. that inftead of the 
friction of the leather of a pifton, when we lift up the pifton 
to make a ftroke, the refiftance neceffary to make the mer- 
cury to rife on the outfide of the barrel iu the outer cylicder 



of the pifton is at leaft as great a3 the friAion we avoid. 
Defaguhers fays, that refiftance is never greater than the 
weight of a concave cylinder of mercury, whofe height is 
the greateft to which the mercury rifes in the faid outer 
cyhnder, and the bafe is the area of the barrel itfelf. This 
weight in a pump of 6 inches bore is equal to 57^ pounds, 
and, therefore, it would appear to be greater than the re- 
fiftance arifing from the fridion of a pifton. But if it be 
confidered, that in the defcent of the pifton for fucking, the 
mercury (hifts immediately into the infide of the barrel, 
rifmg to the fame height therein, and ftill keeping the fame 
bafe, the weight of 57-^ pounds helps to prefs down the 
pifton, and facilitates the overcoming of the force of the 
atmofphere, or, fuAion of the pump ; confcquently, the 
weight of the mercury being balanced is no hindrance, 
whether the pump works with a double or with a fingle 

There remains only then the hindrance by lofs of time, 
whilft the mercury changes from the outfide to the infide of 
the barrel, at the beginning of any ftroke. Defaguliers 
ftates this to be one-fifty-fecond part of the ftroke, and that 
he found the beft pumps then in ufe generally loft near 
one-fifth of the water that they ought to have given, ac- 
cording to their number of ftrokes. 

Notwithftanding the high terms in which this author and 
others have fpoken of the mercurial pump, it can only be 
confidered as an ingenious fuggeftion, for the expence of 
mercury would be too great for the aftual application of 
any fuch machine in practice ; and in refpeft to friftion, it 
would have a confiderable ftiare of refiftance in plunging 
the pifton into the mercury, although there would be no 
aftual rubbing of hard fubftances together. This refiftance 
would arife in the rapid running of the mercury from the 
infide of the barrel to tlie outfide, and back again, at the 
beginning of each ftroke. 

The machine is exceedingly ingenious and refined, and 
there is no doubt but that its performance will exceed that 
of any other pump which raifes the water to the fame 
height, becaufe there can be no want of tightnefs in the 
pifton, and friftion is in a great meafure avoided. But 
thefe advantages are but trifling. The expence would be 
enormous ; for with whatever care the cylinders are made, 
the interval between the inner and outer cylinders muft 
contain a very great quantity of mercury. The middle cy- 
linder muft be made of iron-plate, and without any feam, 
for mercury djflblves every kind of folder. For fuch rea- 
fons, it has never come into ufe. But although we have 
profefted to defcribe only the machines in aftual ufe, it 
would have been unpardonable to have omitted the defcrip- 
tion of an invention, which is fo original and ingenious ; 
and there are fome occaiions where it may be of ufe, fuch 
as nice experiments for illuftrating the theory of hydraulics : 
it would be the beft pifton for meafuring the prefTurcs of 
water in pipes, being in fad the fame principle as the baro- 

SeHor pumps are thofe in which the pifton is made to 
move upon a centre, like a door upon its hinges. The 
pifton is inclofcd witiiin a vcftel fliapcd like the iedor of a 
circle, which forms the body of the pump, and which is 
dinded by the pifton into two compartments. The pifton 
is fitted, fo that it can move backwards and forwards on its 
centre of motion, without fullering any water to pafs by it ; 
and by this motion it will alternately enlarge or contraft the 
capacities of the two compartments, fo as to draw in watir 
through pipes and valves properly fituated, and force it out 
7gain at other pipes. Tliefe kinds of pumps arc difficult to 

conftruS, and have no adv.intages over the pumps witfi 
ftraight barrels, except for the engines for extinguifhing 
fire. See that article for a defcription and figure of Mr. 
Rowntrce's, which is one of the beft of this kind. 

Rotative Pumps. — As moft of the firft movers for hy- 
draulic machinery aft with a rotative motion, it would be 
very dcfirable to have a pump which would at once employ 
the rotative force to the purpofe of raifing water. Many 
fchcmes have been propofcd, and much ingenuity difplayed 
in thefe inventions ; but hitherto no one has been brought 
to fuch pcrfeftion as to be equal to the pumps with ftraight 
barrels. In Ramelli's work, publifhed in 1588, feveral 
rotative pumps arc dcfcribed ; and Leopold has made a 
colleftion of them in his " Theatrum Machinarum Hydrau- 
licarum," vol. i. They are all upon one common prin- 
ciple, viz. a hollow cylinder or drum clofcd on all fides ; 
within this another fmaller cylinder is inclofed, and the in- 
terior cylinder is placed out of the centre of the hollow cy- 
linder, fo that the interior cylinder touches the hollow one 
at one point of the circumference ; but at all other points 
there is a confiderable fpace between the two. The interior 
cylinder is provided with four or fix valves or leaves, which 
are united to it by hinges, and, when folded clofe up to the 
cylinder, will form a fmooth and circular circumference ; 
hut if the leaves are opened out, they will reach to the in- 
terior furface of the hollow cylinder. When the interior 
cylinder is turned round by a handle applied to the axis, the 
valves fweep round within the hollow cylinder, and in this 
motion perform the office of piftons, becaufe they clofe up 
to the internal cylinder, in proportion as they approach to- 
wards the point where the internal cylinder touches the 
hollow cylinder ; and the fame vanes open out again, after 
they liave paffed that point. In this way the fpaces between 
the valves form a number of cavities, which alternately ex- 
pand and contraft in their capacity, and in confequence 
they- will draw up water through a pipe which is inferted 
into the hollow cylinder, and force it out at another pipe, 
fo as to raife up a continual ftrcam. 

The machine is fometimes varied, by making the hollow 
cylinder of an elliptical form : in other cafes, the valves, 
inftead of moving upon hinges, are made to (lide in ftraight 
lines from the centre of the revolving cylinder ; but in either 
cafe, the aftion is the fame. The common defeft of all 
thefe rotatory pumps is, that it is very difficult to pack them 
fo as to be tight, and they have more friftion than any other 
kind of pump. 

The centrifugal pump, invented by Mr. Erfkine, may be 
called a rotative pump, but it is on a different principle 
from all other pumps. A perpendicular pipe has another 
joined to it, in form of tlie letter T : the lower end of this 
pipe being immerfed in water, and the whole filled with 
water, it is turned round on the perpendicular fteni as an 
axis ; the water contained in the horizontal arms will, by its 
centrifugal force, fly out, and draw a conftant ftream of 
water up through the perpendicular pipe. See Centrifugal 

Spiral pump, or Zurich machine, is a hollow drum or cy- 
linder turning on a horizontal axis, and partly plunged in a 
ciftern of water, like a very large grind-ftone. The interior 
fpace of this cylinder or drum is formed into a fpiral canal, 
by a plate coiled up within it, like the main-fpring of a 
watch in its box, only that the fpircs are fituated at a given 
diftance from each other, fo as to form a fpiral paflage of 
uniform width. [&<x Jig. II. Plate IValer-lVoris.) This 
fpiral partition is well joined to the two circular ends of the 
cylinder, and no water can efcape between them. The 


inner end or central part of the fpiral paffage communicates 
with the axis, which is hollow at one end, and communi- 
cates with the vertical pipe which is to convey the water to 
the elevated refervoir. The outermoft turn of the fpiral 
paffage begins to widen at about three-fourths of a circum- 
ference from the open end, and this gradual enlargement 
continues for nearly a femicircle ; this part being called the 
horn. The paffage then widens fuddenly in form of a 
fcoop or ihovel. The cyhnder is fo fupported, that this 
fcoop may, in the courfe of a rotation, dip feveral inches 
into the water, and take up a certain quantity of water be- 
fore it emerges again. This quantity is fufficient to fill the 
enlarged part called the horn, and is alfo nearly equal 
in capacity to one turn of the outermoft uniform fpiral. 
The vertical pipe is connefted with the axis by a turning 
joint, fo as to admit of the rotation of the axis, at the fame 
time that it will not allow of the efcape of any water. 

When this cyhnder is turned round by a handle applied 
to the extremity of the axis, a portion of vsrater which the 
fcoop takes up at every turn, will continually advance in the 
fpiral, until it arrives at the centre ; it will then pafs through 
the hollow in the end of the axle, and will rife upwards in 
the vertical pipe ; and in the intervals between the periods 
when the fcoop dips into the water, the horn will become 
filled with air, and the fucceeding portion of water which is 
taken in will carry the air before it, fo that the water rifes 
in the vertical pipe mixed with air. See Screw. 

Dr. Robinfon, in his account of this machine, recom- 
mends the rifing pipe to be of fmall bore ; for if the pipe is 
fo large as to allow the air to efcape freely upwards through 
the water, the machine will raife the water to a certain 
height, proportioned to the number of turns of the fpiral, 
and to their diameter ; but if the pipe be narrow, fo that 
the air cannot rife freely, it will rife in the pipe almoil as 
(lowly as the water. By this circumftance, the water 
mixed with the air become* of a lefs fpecific gravity, as it 
were, and can be raifed to a much greater height than it 
could be raifed by the mere preffure of the columns of water 
and air in the different turns of the fpiral. This is effefted 
with hardly any augmentation of the power, but if the 
air, after being compreffed, is fuffered to efcape, all the 
force exerted to comprefs it will be loft. The entrance into 
the rifing pipe ftiould be no wider than the laft part of the 
fpiral ; and it would be advifeable to divide it into four 
channels by a thin partition, and then to make the rifing 
pipe very wide, and to put into it a number of flender rods, 
which would divide it into feveral flender channels, that 
would ferve completely to entangle the air among the water. 
This procedure will greatly increafe the height to which the 
heterogeneous column may be carried. 

Another Form of the Spiral Pump. — When the main pipe 
is very high, the former conftruftion will require either an 
enormous diameter of the drum, or many fpiral turns of a 
very narrow pipe. In fuch cafes, it will be much better to 
make the fpiral in the form of a cork-fcrew, than of a flat 
form like a watch-fpring ; or, the pipe which forms the 
fpiral may be wrapped round the fruftum of a cone. 

We regret that we have had no opportunity of making 
experiments upon a machine of this kind, as its principles of 
atlion, though treated of by many authors, are not defcribed 
in a fatisfaAory manner in any works which we have read. 

The chain pump is an effeftive means of raifing water, and 
with the advantage of a continuous motion. It is generally 
made with a fquare or round barrel, placed in a perpendi- 
cular pofition. The chain is furniftied with feveral piftons 
of the fame figure as the barrel, which are fixed at fmall 
diftances afunder upon the links of the chain. The ends of 


the chain are united together, and it is extended between two 
wheels, one fixed at the upper end of the barrel, and the 
other at the lower end ; but fometimes only the wheel at the 
top is ufed. Thefe wheels have forks fixed on the circum- 
ference, which are fo contrived as to receive one half of each of 
the flat piftons in the intervals between the forks, whilft the 
forks take hold of the links of the chain, and draw them up, 
when the wheel is turned round by means of a handle ap- 
plied to the axis. The piftons on the chain are made accu- 
rately to fill the feftion of the barrel, at the lower part near 
the water, and alfo for a few feet upwards ; but above this, 
the barrel is made larger, fo that the piftons rife up free : 
indeed, the upper part of the barrel is only to contain the 
water which is brought up by the piftons, and may, there- 
fore, be fquare, or of any other figure. The lower end of 
the barrel is immerfed in water, and the chain being caufed 
to circulate by turning the wheel, each pifton, as it enters 
into the lower or bored part of the barrel, will bring up 
water before it in the barrel ; which water will rife in the 
upper part of the barrel, till it runs over the top ; and as the 
piftons fucceed each other in a regular fucceflion, they pro- 
duce a conftant ftream. Chain pumps are chiefly ufed in 
fliips, where they are worked by the force of men turning 
winches. ( See Pump.) In other fituations they are moved 
by horfes, and fometimes by the impulfe of a ftream of water. 
They are fo contrived, that by the continual folding in of the 
piftons, when they enter into the bottom of the barrel, 
ftones, dirt, or whatever comes in the way, may be cleared 
off. On this account they are often ufed to drain ponds 
and fewers, or to remove foul water, when no other pump 
could be employed. 

The greateft difadvantage in the chain pump is the fric- 
tion of the chain, and of the piftons, whicli is greater than 
in other pumps ; becaufe feveral piftons are moving in the 
barrel at the fame time, and alfo becaufe the piftons do not 
admit of the application of the cup-leathers, which we have 
defcribed. The edges of the cups would fold up when 
they enter into the barrel, and get between the edge of 
the pifton and the barrel. The piftons are, therefore, 
made with a thick piece of leather, which is placed be- 
tween two round plates, which form the pifton or faucer, 
as it is called ; the leather is cut round to the fize of the 
barrel, fo that the edge of the leather may be applied to 
the infide of the barrel. In this way, its tightnefs rauft 
depend wholly upon the force with which the leather is 
fqueezed into the barrel, and it occafions great friftion to 
make the piftons fufficiently tight. 

Another variety of the chain pump is an endlefs rope,' 
with ftuffed cuftiions faftened upon it at regular intervals. 
By means of two wheels or drums, the rope is made to cir- 
culate, and the cufhions are drawn up in fucceffion through 
the barrel, and each one carries fome water before it. 

The chain pump is found to raife a greater quantity of 
water to the fame height, when the barrel is placed in an 
inchned pofition, than when vertical. M. Belidor recom- 
mends the barrel to be placed at an angle of 24 degrees with 
the horizon, and the diftance between the piftons to be 
equal to their diameter. The reafon of this advantage is, 
that an inchned pump afts with lefs friftion, becaufe the 
piftons need not be fo exaftly fitted, but they will, by their 
weight alone, apply clofely to the bottom or loweft fide of 
the mchned barrel ; whereas the piftons of the vertical pump 
muft exaftly fill the barrel, or the water will leak down 
from one to the next in a conftant ttream. 

Bellows-Pump A pair of leathern bellows may be em- 
ployed as a pump, if a fuftion-pipe is applied to the lower 
valve, and another pipe to the nozzle, with a valve to 
G prevent 


prevent the water returning into tlie bellows after it has 
been driven out by clofing the bellow?. This kind of 
pump has been frequently propofed, and the advantages of 
difpcnfing with barrels and pillons loudly infilled upon ; but 
the refiftance of the leather in folding, and the lofs of water 
by leakage, and above all the want of durability, will always 
prevent tifie adoption of fuch pumps. 

Tht Pump -with a Diaphragm of Leather, which doei not 
Jlide'mthe Barrel. — This is very nearly allied to the bellows- 
pump- The belt form for conllruAing it is fully defcribed 
in our article Ship'/ Pump, where the mvcntion is attributed 
to Benjamin Martin ; but we find the fame thing was long 
before apphed by MeCfrs. GofTet and De la Deuille, in 
France. ( See Belidor's Arch. Hydrauliqiie, vol. ii. p. 120.) 
This is a good pump, but is not durable, becaufe the con- 
flant ftrain on the leather Avill caufe it to crack. 

Suci'mg-Pumff, -which gives out a continual Stream. — Mr. 
Sraeaton applied the following fimple and effeftual expe- 
dient to make a fingle fucking-pump deliver the water 
equally in the defcent of the bucket as in its afcent. The 
pump-rod was enlarged, by furrounding it with a cylinder of 
wood at the part where it rofe above the furface of the 
water contained in the ciitern at the top of the pump. This 
cylinder of wood was of fuch diameter, that its feAion 
was equal to half the area of the pump-barrel at the 
place where the bucket worked. When the bucket was 
drawn up, and raifed water into the ciftern at top of the 
pump, the wood cylinder, which was attached to the pump- 
rod, rofe up out of the water in the ciftern, and thereby 
made place in the ciftern for one -half of the water which was 
brought up by the bucket, and in confequence only one-half 
of the water ran out at the fpout of thecilUrn ; but when the 
bucket moved downwards, in order to fetch another ftroke, 
this cylinder of wood difplaced from the ciftern half as much 
water as the pump brought up in the former inftance, and 
confequently an equal quantity of water was given out at 
the fpout in either cafe. 

If the pump is worked by the force of a man working a 
fimple lever, then lie will make the down-ftroke of the 
bucket in lefs time than the up-ftroke, and in this cafe the 
area of the cyhnder (hould be made lefs than half the area of 
the barrel of the pump. It muft be obferved, that this 
contrivance is only a remedy for the unequal efflux of water 
from the fucking-pump, and that the power required to 
work the pump is ftill left unequal in the up-ftroke and 
dowrn-ftroke, becaufe it is only in raifing up the bucket that 
the water is drawn from the well below ; and that water 
which runs out at the fpout when the bucket defcends, is 
drawn from the ciftern at the top of the pump, and not from 
the well. When the pump is worked by a man with a 
lever, this inequality of the refiftance is advantageous, be- 
caufe a man can exert his force moft conveniently when he 
depreffes the end of the lever to draw up the bucket ; alfo, 
in a fingle-afting fteam-engine, the principal power is 
exerted to draw up the bucket. 

In machines worked by wind, water, or horfes, the moving 
force is uniform, and the refiftance muft, by fome means, be 
made uniform alfo, or the machine will move by fudden ftarts. 
A fufficient weight maybe applied to theoppofiteendof the 
lever to counterbalance one-half of the force neceflary to draw 
up the bucket ; this weight will tend to diminifti the force of 
drawing up the bucket, and when the bucket defcends, and 
the machine would otherwife have nothing to do, it will 
have to raife up the weight ready to aid it in the fucceed- 
ing ftroke. Or a fly-wheel may be applied : but a ftill 
better method is to employ two pumps to aA alternately, by 
wliich means the refiftance ii continual, and the efflux of 

water alfo. When two fucking-pumps are employed, ihcy 
may be combined together, by making them botli draw 
from a common fu(flion-pipe, and both may be made to lift 
the water into the fame ciftern. Or two or three force- 
pumps may be combined together, as is defcribed in the 
article Pump, in order to produce a continuous ftream. 

Air-VeJJrl for equalizing the Difcharge of WaUr from 
Pumps. — This is the moil perfeft contrivance for effetling 
that purpofe. It is a clofe veftel of any figure,,which will 
contain air, and is made to communicate with the pipe 
which conveys the water away from the pump. This com- 
munication muft be made at the lower part of the air-vefiel, 
fo that the water will have free ingrefs and egrefs from it. 
The air in this vefTel will be comprefTed into a Imaller fpace, 
in proportion to the column of water which the pump has 
to raife ; and by its elafticity endeavouring continually tore- 
gain its former fpace, it will aft as a fpring to equalize all 
fudden motions of the water through the pipe ; for in any 
pump which afts by a barrel and pifton, the water will be 
propelled by ftarts ; and even if two or three barrels arc 
combined together fo as to produce a continual efflux of 
water, fuch efflux will not be perfectly equal during all the 
periods of the motion. 

The evil of this may appear trifling and fo it would be 
merely with refpeft to the difcharge of the water ; but it mull 
be confidered that the mafs of water contained in a long 
pipe is very great, and that it requires a very confiderable 
force to put this mafs in motion with that velocity willi 
which it muft flow through the pipe. Now if the 
operation of a pump is by ftartsn the mafs of water in 
the main-pipe will remain at reft, prefling on the valve 
during the time that the pifton is withdrawn from the bot- 
tom of the working barrel. In this cafe, the force necel- 
fary to put the water in motion muft be expended at every 
ftroke, becaufe if the column conies to reft only for an 
inftant, it muft be put in motion again before the operation 
can be refumed : this is a heavy additional load upon the 
firft mover, and has another more ferious evil in ftraiiiing the 
pipe and all parts of the machinery ; becaufe the column of 
water in the pipe, after it ftops, runs back for a fmall 
fpace until the valve fhuts ; and it makes juil as great a con- 
cuflion or ftiock when its motion is fuddenly flopped by the 
fliutting of the valve, as any other folid body would do 
which was of the fame weight, and moved with the fame 
velocity. In large ftcam-engincs, the fliock occaGoned by 
the ftiutting of the valve is exceedingly violent, unlefs an 
air-vefiel is applied. In that cafe, if the pump urges the 
water with a fudden motion, the air in the vefiel will yield, and 
admit the water into the veflel in far lefs time than the whole 
column of water could be urged into motion ; but as the air 
will become comprefled by more force than the column of 
water in the pipe, the elafticity of the air will force the 
water from the vefiel and up the pipe with a regular mo- 
tion, and this will continue until the air has regained fo 
much fpace that its elafticity is only juft fufficient to ba- 
lance the column of water in the pipe. 

The air-vefiel ftiould be placed as near the pump as pof- 
fiblc, that it may produce an equable motion of the water in 
the whole length of pipe. The air-vefiel is of confiderable 
advantage when a column of water of great length is to be 
raifed by a finglc-afting pump. If the pifton ol the pump 
at one end of the pipe is put at once into motion, even with 
a moderate velocity, the ftrain on the pipe would be very 
great before the column of water could be put in motion. 
But the air-vefiel tends to make the motion along the main- 
pipe lefs defultory, and therefore diminiflies tliofc ftrain* 
which would really take place in the pipe. It afts 
2 bkc 


like the fprings of a travelling carriage, whofe jolts are in- 
comparably lefs than thofc of a cart, and by this means 
really enables a given force to propel a greater quantity of 
water in the fame time. 

The ttream produced by the afliftance of an air-veflel is 
almoft perfeftly equable, and as much water runs out dur- 
ing the returning of the pifton as during its aftive ftroke ; 
but it muft not be imagined that it therefore doubles the 
quantity of water. No more water can run out than what 
is fent forwards by the pillon during its effeAire ftroke. 
The continued ftream is produced only by retaining part of 
this water in the air-veflel during the ftroke of the pifton, 
and by providing a propelling force to aft during the pif- 
ton's return ; but it cannot enable the moving force of the 
pifton to produce an increafedeffeft : forthecompreffion which 
is produced in the air-veflel, more than what is neceflary for 
merely balancing the quiefcent column of water, reafts on the 
pifton to refift its comprefiion juit as much as the addition of 
a column of water would do, the height of fuch column being 
fulficient to produce the required velocity of the efflux. 

Machines for ivork'mg Pumps. — The beil method of work- 
ing pumps from a firft mover which afts with a rotative mo- 
tion, is by means of cranks ; and if two or more pumps are 
to be aftuated by the fame machine, the cranks for them 
fhould be placed at regular inter^•als round the centre, £o as 
to produce a continual aftion. 

It has been obferved, in our article 5TEA.u-Engine, that 
the reciprocating motion obtained by a crank is very un- 
equal, even when the rotative motion of the crank is quite 
uniform. This renders the motion of the pifton in the bar- 
rel of the pump irregular, for at the top and bottom of the 
barrel the motion of the pifton is very flow, but when the 
pifton is at the middle of the barrel the pifton moves 
quickly. This property is a great advantage in working 
pumps, becaufe it puts the column of water in motion with 
a lefs fudden fl^ock ; but it has been very generally miftaken 
and confidered as a defecl, and many ingenious contrivances 
have been propofed, by means of racks and pinions, to give 
an uniform motion to the pifton-rods of pumps. Thefe have 
never fucceeded in praftice, and have always been laid afide. 
The attempts of mechanicians to correft this unequal 
motion of the pifton-rod are mifplaeed ; for if it could be 
done it would greatly injure the performance of the pump. 
As this is a favourite fpeculation, and new attempts to 
perfeft it are conftanily making, we think it right to fliew 
the reafon of their failure. 

Suppofe the firft mover to move uniformly with a rotatory 
motion, and that the machinery is fo conftrufted, that the 
pifton-rod will be moved up and down with a regular mo- 
tion, or that the velocity of the pifton (hall be at all times 
the fame, whether it is at the top or bottom, or in the 
middle of its courfe. In this cafe, at every reciprocation, 
the column of water in the main pipe muft be fuddenly 
urged into motion from a ftate of reft, and the machine 
could not perform one ftroke, if the velocity of the firft 
mover did not flacken a little, or if the different parts of the 
machine did not yield by bending or comprefiion. Thefe 
ftrains would be fo fudden and violent, that no ftrength of 
materials could withftand the violence of the ftiocks at every 
reciprocation of the motion. This would be chiefly ex- 
perienced in great works which are put in motion by a 
water-wheel, or fome other equal power, exerted on a large 
inafs of matter, of which the machine confifts. The water- 
wheel, being of great weight, moves with fteadinefs or uni- 
formity ; and when an additional refiftance is oppofed to it 
by the beginning of a new ftroke of the pifton, its quantity 
of motioB is but little affefted by this addition, and it pro- 

ceeds with very little lofs of motion. The machine muft 
therefore yield a little by bending and comprefiion, or it 
muft break to pieces, which is the common event. 

A crank is free from this inconvenience, becaufe it ac- 
celerates the pifton gradually, and brings it gradually to reft, 
while the water-wheel moves round with almoft perfeft uni- 
formity. It has been ftated as an inconvenience of this flow 
motion of the pifton at the beginning of its ftroke, that the 
valves do not (hut with rapidity, fo that fome water gets 
back through them ; but this is a miftake, becaufe the valves 
always fall by their own weight as foon as the water ceafes 
to flow upwards through them. Now when the pifton be- 
gins to move with its flow motion towards the end of the 
ftroke, lefs water is caufed to flow through the valves, and 
in confequence they clofe gradually, and will be fully (hut 
by the time that the pifton becomes motionlefs, and before it 
begins to return. This is (hewn in the large machines, fuch 
as that of London-bridge, where the pumps are worked by 
cranks, and the valves clofe imperceptibly ; but in a fteam- 
engine of the fame power, the (hock occaHoned by the (hut- 
ting of the valves is exceedingly violent. In (hort, by a 
judicious application of the crank and a fly-wheel, or an air- 
ve(rel, and by employing two or three barrels to the pump, 
the evils of the reciprocating motion of pumps may be com- 
pletely remedied, and on this account we confider, that if a 
rotatory pump could be brought to perfeftion, it would have 
no fuperiority over an accurate pump with a ftraight barrel. 
Mr. Struaton's proportions for a two-horfe pump machine for 
raifing water are as follow : horfe-track thirty feet diame- 
ter ; great cog-wheel nineteen feet diameter, with 1 44 cogs ; 
this gave motion to a trundle of feventeen ftaves, fixed upon 
an horizontal axis, which carried a caft-iron fly-wheel of ten 
feet diameter, and the rim three inches by three inches. On 
the extremity of the horizontal axis was a crank of a foot 
and a half in length, which, by means of a connefting-rod, 
gave motion to one end of a working beam or lever of feven- 
teen feet long, which was poifed on a centre in the middle 
of its length, and at the oppofite end was an arched feftor 
for the chain, by which the pump-rod was fufpended. The 
pump was a fucking-pump, fix inches diameter in the barrel, 
and the length of the ftroke was three feet. A weight was 
applied to the end of the beam over the crank, which was 
fufficient to balance one-half of the column of water in the 
pump. In this machine, when the horfes walked two miles 
and a half per hour, they made two turns and one-third /fr 
minute. The trundle and fly-wheel made twenty turns per 
minute ; the pump made the fame number of effedive ftrokes, 
and raifed upwards of a hundred barrels ale meafure/irr hour. 
By the counter balance and the fly-wheel, the refiftance to 
the horfes was rendered perfeftly uniform. 

The Ptimp Machine at Bhnheim, which was erefted by 
Mr. Alderfea for the duke of Marlborough, is thus de- 
fcribed by Mr. Fergufon in his leftures. The water-wheel 
is underfhot, and is turned by the fall of the water running 
down an inclined plane, and (biking the fl«ats of the wheel. 
The extremity of the pivot or gudgeon is formed into any 
number of cranks; for inftance Tii^ that is, three at each end 
of the axis, more or lefs, according to the force of the fall 
of water, and the height to which the water is intended to 
be raifed by the engine. As the water-wheel turns round, 
thefe cranks move as many levers up and down, by the iron 
connefting-rods. Thtfe levers alternately raife and deprefs 
the piftons of the forcing-pumps by other iron rods, which 
are attached to the oppofite ends of the levers, and as one 
is raifed the oppofite pifton is deprelTed. Pipes go from 
all thefe pumps, to convey the water which they draw up 
(to a fmall height) into a clofe ciftern or box, from which 
G 2 the 


the main-pipe proceeds, the water is forced into this ciftern wheel, fix feet diameter, with forty-eight cogs. To this is 
by the dcfcent of the piilons. And each pipe, going from applied a trundle, or pinion, of fix rounds, or teeth ; anil 
Its refpedive pump into the ciltem, has a valve to cover upon the fame axis is 6xed a fecond cog-wheel, of fifty-one 
its end in the ciftern, which valves will hinder the return cogi ; laftly, this is turned by a trundle of fix rounds, on 
of the water by the pipes ; and, therefore, when the cif- whofe axis is a winch or windlafs. The other lever is pro- 
tern is once full, each pifton upon its defcent will force the vidod with a fimilar chain and wheel-work, and the axis 
water (conveyed into the ciftern by a former ftrokc) up the of the laft-mentioncd trundle is prolonged until the two 
main-pipe, to the height to which the engine is intenJvd to winches nearly meet, fo that one man, with the two wind- 
raife it ; which height depends upon the quantity to be raifed lafles, raifes or lets down the wheel, as there is occafion to 
and the power that turns the wheel. When the power upon dip always equally into the water. 

the wheel is Icffcned by any defedl of the quantity of water By means of this machine, the ftrength of an ordin.iry 
turning it, a proportionable number of the pumps may be man will raife about fifty ton weight, which much exceeds 
laid afide, by difengaging their rods from the vibrating the weight of the water-wheel. 

lexers. Near each end of the great axis of the water-wheel, a 

When fuch a machine is placed in a flream that runs cog-wheel is fixed, eight feet diameter, and forty-four cogs, 
open a fmall dccHvity, the motion of the levers, and aAion working into a trundle, of four feet and a half diameter, and 
of the pumps, will be but flow ; fince the wheel muft go twenty rounds, whofe axis or fpindle is of caft-iron four 
once round for each ftroke of the pumps. But when there inches in diameter, lying in braiTcs at each end, fupported 
is a large body of flow running water, a cog or fpur-wheel by ftrong timber framing. 

may be placed upon each fide of the water-wheel, upon its And becaufe the fulcrums of the levers above defcribed 
axis, to turn a trundle upon each fide ; the cranks being are in the line of the axis of the trundle, in what fituation 
formed upon the axis of the trundle. And by proportion- foever the water-wheel is raifed or let down, the great cog- 
ing the cog-wheels to the trundles, the motion of the wheel is always equidillant from the trundle, and works 
pumps may be made quicker, according to the quantity and or geers truly therewith. 

ttrength of the water upon the firft wheel ; which may be A quadruple crank of caft-iron is attached to the end of 
at great as the workman pleafes, according to the length the axis of the trundle, the metal being fix inches fquare, 
and breadth of the float -boards- of the wheel. In this man- each of the necks being diftant one foot from the centre of 
ncr the engine for raifing water at London-bridge is con- motion ; the gudgeons of the cranks are fuftained in braffes 
ftrufted ; which we ftiall now proceed to defcribe. at each end in two headftocks fattened down by caps. One 

The original engine at London-bridge was put up by end of this crank is placed clofe abutting to the end of the 
Mr. Sorocold towards the beginning of the laft century : axis of the trundle, which at that end is fix inches diame- 
it deferves notice on account of a contrivance for raifing ter, and having a flit in the end, the end of the crank ter- 
and falling the water-wheel, to accommodate it to the dif- minates in the fame manner, and an iron wedge is put, one 
ferent heights of the water : this was the invention of Mr. half into the flit in the end of the axis, and the other half 
Hadley, who put up the firft of that kind at Worcefler, into the flit in the end of the crank, by means of which the 
for which he obtained a patent. axis turns the crank about with it. 

Mr. Beighton has thus defcribed this machine in the Phi- The four necks of the crank have each an iron fpear, or 
lofophical Tranfaftions. The wheels of the London-bridge rod, jointed to them, and alfo jointed at the upper end to 
water-works are placed under the arches of the bridge, and the refpeftive libra, or lever, within nine feet of the centre 
moved by the common ftream of the tide-water of the river, of the lever. Thefe levers are twenty-four feet long, mov- 
The following are the particulars of the largeft wheel. ing on centres in the middle of their length, and fupported 

The axle-tree of the water-wheel is nineteen feet long, by the frame ; at each end of each lever is jointed a rod, 
and three feet in diameter, in which are four fets of arms, which defcends into the pump-barrel, and has the forcer faf- 
eight in each fet ; thefe arms fupport four circular rings or tened to it. Each end of the four levers works a quadruple 
felloes, twenty feet in diameter, to which are attached the forcing-pump, confifting of four caft-iron barrels or cyhn- 
float-boards, fourteen feet long and eighteen inches deep, ders four feet three-quarters long, feven inches bore above, 
being about twenty-fix in number. The wheel lies with its and nine inches below, where the valves lie ; the four bar- 
two gudgeons, or centre-pins, upon brafles in two great rels are faftcned by fcrewed flanches over four holes in a 
levers, which are placed in an horizontal pofition, and there- hollow trunk of caft-iron, having four valves in it juft over 
tore fupport the weight of the wheel. The wheel is, by thefe holes, at the joining on of the bottom of the barrels, 
thefe levers, made to rife and fall with the tide in the fol- and at one end of the hollow trunk is a fucking-pipe and 
lowing manner. The levers are fixteen feet long ; thus, grate, going into the water, which fupplics all the four 
from the fulcrum of each lever, to where the gudgeon of pumps alternately, when they fuck or draw up water, 
the water-wheel bears on it, fix feet ; and from thence to To carry away the water which they force out, there 
the extremity ten feet. At the extremity is a feftor or proceeds from the lower part of each pump-barrel, a neck 
arch of a circle defcribed from the fulcrum of the lever, turning upward arch-wife, whofe upper part is caft with a 
and to the bottom of this arch is fixed a ftrong triple chain, flanch to fcrew up to the under fide of another fquare trunk, 
made after the fafliion of a watch-chain ; but the links are which receives the necks of all the four barrels ; which 
arched to a circle of one foot diameter, having notches, or necks have bores of feven inches diameter, and over the 
teeth, to take hold of the leaves of a pinion of caft-iron, holes in the trunk, communicating with them, are placed 
ten inches diameter, with eight teeth in it moving on an four valves at the joinings or flanches. The fquare forcing- 
axis, which is fixed up over the arch at a confiderable trunk is caft with four bofles, or protuberances, ftanding 
height, and the chain goes up to the pinion and turns over out againft the valves, to give room for their opening and 
it. The other loofe end of this chain has a large weight fliutting ; and on the upper fide of the trunk are four holes 
hanging at it, to help to counterpoife the great weight of ftoppcd with plugs, to take out on occafion, to cleanfe the 
the water-wheel, and prevent the chain from Aiding on the valves. One end of this trunk is flopped by a large plug, 
pinion. On the fame axis a» the pinion is fixed a cog- and to the other the iron-pipct arc joined by flanches, 



tlu'ougli which the water is forced up a hundred and twenty 
feet, or to any height or place required. 

See a drawing of a triple forcing-pump of this fame 
kind, in our article Pump. 

Befides this foiir-barrellcd pump, there is fuch another 
placed at the other ends of the librae, or levers ; but to 
avoid confufion, we fpoke only of one quadruple pump, as 
the other is jufl the fame ; but its rods and forcers being at 
the oppofite ends of the levers, the barrels draw and force 

At the other end of the water-wheel is placed all the 
fame fort of work as at the end already defcribed ; v'f^. 
the great cog-wheel and the trundle, fixed upon the fpindle 
or axis, which is united, as before-mentioned, with the axis 
of the quadruple crank. 

Alfo the four rods from thefe cranks, to work the four 
horizontal levers, each of which has a forcer at both 
ends, to ferve the four barrels of a quadruple pump at each 
end of the levers ; fo that one Cngle wheel works fixteen 
pumps, viz. two quadruple engines at each end of the axis. 

Mr. Beighton, who has defcribed the ftrudlure and ope- 
ration of this engine, (fee Phil. Tranf. abr. vol. vi. p. 358.) 
has thus calculated the quantity of water raifed by it in a 
given time. 

In the firft arch next the city there is one wheel with 
double work of fixteen forcers. In the third arch, one 
wheel with double work at one end, and fingle at the other, 
having twelve forcers. A fecond wheel in the middle hav- 
ing eight forcers. A third wheel with fixteen ; fo that 
there are in all fifty-two forcers. One revolution of a 
wheel produces in every forcer 2^ ftrokes ; fo that one 
turn of the four wheels makes 1 14 ftrokes, taking all the 
barrels into account. When the river afts with moft ad- 
vantage, the wheels go fix times round in a minute, and 
but 45 at middle tide ; hence the number of ftrokes in a 
minute is 684 ; and as the ftroke is two feet and a half 
in a feven-inch bore, it raifes four ale gallons ; and all raife 
^<T minute 2736 ale gallons; i.e. 1 64 1 60 gallons or 3420 
hogflieads /i^r hour, ale meafure, to the height of 120 feet. 
Such is the utmoft quantity they can raife, fuppofing that 
there were no imperfeftions or lofs at all ; but Mr. Beigh- 
ton infers, from experiments performed on engines whofe 
parts were large and excellently conftrufted, that they will 
lofe one-fifth and fometimes one-fourth of the calculated 

Mr. Beighton obferves, that, though thefe water-works 
may juftly be efteemed as good as any in Europe, yet fome 
things might be altered much for the better. If, he fays, 
inftead of fixteen forcers, they worked only eight, the 
ftroke might be five feet in each forcer, which would draw 
much more water with the fame power in the wheel ; be- 
caufe much water is loft by the too frequent opening and 
/hutting of the valves ; and that the bores that carry off the 
water from the forcers are too fmall ; and that they ftiould 
be near nine inches in diameter. This objeftion Dr. Defa- 
guliers fays is of no force, unlefs the velocity of the piftons 
was very great ; but here the velocity of the water pafling 
through the bores is much lefs than two feet in a fecond. 
This laft writer obferves, that a triple crank diftributes the 
power better than a quadruple one. He adds, that forcers 
made with thin leather tanned, of about the thicknefs of 
the upper leather of a countryman's ftioe, would be much 
better than thofe of the ftiff leather conmionly ufed. 

In order to calculate the power which the above water- 
wheel exerts, we muft find the weight which it raifes, and 
the fpace through which it is raifed in any given time. 

The weight of the column of water, in any one of the 

pumps, is found thus: Diameter feven inches fquared :a 
49 circular inches area. Now one cylindrical inch, a foot 
high, weighs .34 pounds avoirdupois, and therefore 49 fuch 
cylinders muft weigh 16 j pounds; but the column is I20 
feet high, and therefore 120 x i6| = '999 pounds weight. 
This column of water is raifed 2i feet at every ftroke, now 
each pump makes 2^ eff'edive ftrokes for every turn of the 
wheel, or taking the wheel at fix turns per minute, each 
pump makes 13.2 Hiokes per minute. Multiply this by 2^ 
feet, and we find the motion given to each column of water is 
near 33 feet in a minute, and the weight of it 1999 pounds. 

Biit the wheel wliich we have defcribed aftuates 16 fuch 
columns, and therefore the total weight will be 3 1984 lbs. 
raifed 33 feet in a minute. This is equal to 105557 j lbs. 
raifed one foot high per minute. 

What is called a horfe-power, in fteam-engines, is 33000 
pounds raifed one foot high per minute, and we find this 
contained near thirty-two times in the above quantity, fo 
that this fingle machine exerts thirty-two horfe-power. But 
as the above horfe-power is lA times what horfes can do for 
conftant work, it would take forty-nine horfes to do as 
much work as this wheel, and they would not be able to 
work more than eight hours every day, but the water-wheel 
works five or fix hours each tide. 

We ftiall afterwards give a fimilar calculation of the ma- 
chine at Marly, in France, in the fame terms, fo as to admit 
of a direft comparifon, and from this it will appear, that the 
old machine at London-bridge, which was erefted not long 
after the machine at Marly, is three times as powerful as any 
one of the water-wheels at Marly. 

The above ftatement of the wheel making fix turns /fr 
minute is taken from Mr. Beighton's account, who alfo 
ftates the velocity of the water at 685 feet per minute, and 
the velocity of the wheel 3 10 feet per minute, or as i to 2.2. 

In 1763 Mr. Smeaton found, by an average of the fix years 
preceding, that the engine above defcribed had made 3025 
ftrokes in each pump at every tide, taking an average of all 
the circumftances of high and low tides. This is only 1375 
turns for the water-wheel, or 4033 ale hogftieads every 
twelve hours ; and hence the produce falls very ftiort of the 
calculation of fix turns per minute ; but this does not affeft 
the power of the machine during the fhort time when it is 
working at that rate. 

In 1762, when the two middle arches of London-bridge 
were thrown into one by the removal of the pier, the 
water way of the river was fo much increafed, that the 
water-wheels did not perfonn fo much as they did before, 
the daily produce being reduced to 2716 hoglheads. In 
confequence, the city granted to the Water-works Com- 
pany the ufe of the fifth arch, for which Mr. Smeaton 
planned a larger machine than any of the others : it was 
erefted in 1767, and which we ftiall now defcribe. 

We fuppofe it underftood, that London-bridge is not 
built with ftone down the bottom of the river, but accord- 
ing to an ancient method of driving piles into the bottom 
of the river, and cutting off' the tops level with the loweft 
water line, upon thefe the ftone-piers of the bridge are 
erefted ; but as the original piles were fubjeft to decay, and 
admitted of no renewal, it became neceffary to furround 
them with gravel and chalk ; and to retain the chalk, caf- 
ings of piles, called ftarlings, are driven in all round the 
piers. Thefe diminifti the fpace between the arches, fo as to 
occafion a very rapid current of the water in running 
through them, becaufe the water-paftage bears only a fmall 
proportion of the artificial folids, thus placed in the way of 
the current, and this reduces nearly all the arches to fluices 
as it were. Of the twenty arches in this bridge, fix are 



devoted to the water-machine;, that is, five on the London 
fide, and one on the Southwark fide. 

Mr. Smeaton's great Engine at the fflh Arch of London 

Bridge Tl is machine is reprefented in pcrfpcAive, in 

Plate II. Water-works, Machines for raifing Water. The 
view being taken from beneath the arch of the bridge, B B 
reprefents the ftarhng of the fourth pier of the bridge, 
compofed of a vaft body of piles driven into the bed of the 
river, and the interfticcs filled up with chalk and gravel. 
Upon the heads of thefe piles, a fet of horizontal beams 
are laid in the manner of joills, and all is made level by chalk 
and gravel. 

The fifth pier C C is made in the fame manner. The 
water-wheel F F G G is made of fuch a breadth as to fill 
the fpace between the two ftarlings as exadly as poflible, 
without touching ; and the bearings for the gudgeons of 
its axis are fupported upon head-ilocks E E^ which reft 
upon the ftarlings. The water-wheel has four circular 
rings F F F F, each fuftained by fix arms mortifed into the 
axis ; each ring has twenty-four ftarts mortifed into it, and 
to thefe are nailed the float-boards//, upon which the water 
afts to turn the wheel round. 

Upon each end of the main axis is fixed a large wooden 
wheel H H, round which caft-iron rings of cogs are fixed 
in fegments. Thefe cog-wheels turn two trundles, which 
give motion to the forcing-pumps, which are fix in number, 
via. one three-barrelled pump on each fide of the water- 
wheel ; but only one of the engines or triple pumps is (hewn 
in the figure, for as the other is exaftly the fame, it is fuf- 
ficient to defcribe one. The axis on which the trundle I is 
fixed is of caft-iron ; it is connefted with a triple crank, one 
arm of which is marked b, and two others are hidden behind 
the frame : g hi are ftrong iron rods, joined to the cranks at 
their lower ends, and to the ends of the great levers or re- 
gulators K L M at the upper ends. 

The regulators are poifed on centres in the middle of 
their length, and have arches i/m at the other ends, which 
are ftruck from the centres of motion, upon which arches 
the chains are laid, to give motion to the pifton-rods of the 
pumps N. 

By the motion of the water ftriking the float-boards, the 
water-wheel is made to revolve on its axis, and the large cog- 
wheel H with it. This turns the trundle I and the triple 
cranks ic, which, being arranged round the axis at equal in- 
tervals, elevate and deprefs the crank-rods g h i and regula- 
tors K L M fuccelTively, and give to the pump-rods and 
piftons a vertical motion. 

The joints of the crank-rods ^A« are made to fcrew to- 
gether round the crank-neck with brafs between ; by this 
means they work very pleafantly, and when worn can be 
fcrewed up tight again that they may have no fhake. The 
crank-rods are each made in two lengths, each of which has 
a flanch at the end, and they join at n in the middle of the 
rod : the flanches are held together by three fcrews, fo as 
they may be taken apart occafionally without difficulty, 
when the pump-forcers are to be drawn out of the barrels 
to new leather them. 

The joints at the end of the beam or levers are made 
with braffcs, and fcrews to adjuft them ; and fo are the cen- 
tres or fulcrums of the levers. 

The levers or regulators are admirably well defigned to 
b« ftrong, with but little timber ; they are formed of two 
pieces of timber, between which the caft-iron axis on which 
they turn are placed ; and then the ends of thefe pieces are 
bent to touch, and are kept together by hoops and fcrew- 
bolts, fo as to make rlofe joints. At the cndu, feveral fmatl 
fquare pieces of wood are interpofcd crofs ways in thefe 

joints at the ends of the lever, being let into both timbers ; 
by thefe, when they are firmly bound togetlier, tiie two 
pieces of timber are prevented from Hiding end ways upon 
each other, fo as they form an excellent trufs-beam, for it 
cannot bend or yield without ftretching one timber and 
comprefFing the other. 

The pump-i-ods are attached to the arches at the ends of 
the beams by four iron chains each, as is fticwn in fir. 2. 
The rod has a crofs-piece p fixed on the top of it, to which 
the two outfide chains arc attached, and the lower ends of 
the fame chains are faftcned at tlie lower end of the arch. 

Thefe chains atl to pull down the pifton-rods ; the other 
two chains which return or raife the rods are faftened to the 
top of the arch, and to the rods at the lower ends, as- fhewn 
in the figure. 

The pumps are forcing-pumps, and raife the watsr when 
the piftons are deprefled : the lower piece of the triple 
pump is a fquare iron-pipe or trunk, fcrewed faft down 
upon the groundfells of the engine-frame ; this is called the 
fuftion-piece : it has a flancii at each end, to one of which a 
hd is fcrewed, and the other joins it to the fuftion-pipe R, 
which brings up the water from the river. On the top of 
the trunk, the three barrels N are fcrewed, each having 
a valve in the joint, which allows water to enter into the 
barrel, but prevents its return. From the bottom part of 
each barrel proceeds a crooked pipe q, which communicates 
with another fquare trunk S, called the forcing-piece, hav- 
ing valves at the joint, to prevent any water from getting back 
into the barrels. On the top of the trunk over each valve 
is a round hole, over which a lid is fcrewed, but can be re- 
moved to clean or repair the valves when neceffary. Similar 
lids are fcrewed on over openings into the fudlion-trunk, at 
the back towards the cranks. At the ends of the forcing- 
trunk S are flanches, one of which receives a lid like the 
lower trunk, and the other flanch joins to the pipe t, which 
conveys the water away from the pumps. 

The piftons or buckets of the pumps are folid, that is, 
without valves in them ; and their adtion is as follows : 

When the pifton of any of the barrels is drawn up, it 
makes a vacuum in that barrel ; and the prefTure of the at- 
mofphere on the furface of the water from whict\ the fuftion- 
pipe R draws, raifes the valve at the bottom of that barrel, 
and fills it with water. At the defcent of the pifton, the 
lower valve fhuts, and the water contained in the barrel can 
find no paftage but through the valve in the forcing-trunk 
S ; and when the pifton is drawn up again this valve dofes, 
and the lower one opens to give a frelh fupply of water to 
the barrel. By the pofition of the triple cranks, it always 
happens that one or other of the barrels is forcing the 
water into the force-pipes ; and as the llrokes of the other 
fet of pumps at the other end of tlie water-wheel are con- 
trived to be intermediate or alternating to thefe, a conftant 
fucceflion is kept up. 

The main-pipe s is continued to the ftiore, to convey the 
water into the ftrects. A wooden ciftern T is placed over 
the pumps to hold water, and keep a conftant fupply of it 
above the piftons to prevent leakage. The whole engine is 
furrounded by a ftrong timber fence, which guards it from 
the injuries it might receive from vcflels or floating ice, 
ftriking it at high water, when the water rifes above the 
level of the ftarlings nearly to the axis of the water-wheel. 
On the tops of thefe piles, a large ftage is built, to ferve as 
a road from the (hore to the engme, and the underfide of it 
fupports the main-pipes, which convey the water afhore. 
There arc alfo other ([.iges in difFercut parts of the machine, 
to fupport workmen when repairing it ; thefe prevent thp 
whole engine from being fecn from the bridge atone view, and 



Tor this reafon they are omitted in the drawing, which is in 
fome degree imaginary, as it reprefents the engine detached. 

This machine is more Ample than the preceding, as it 
performs more work by fix pumps of ten inches bore and 
4^ feet ftroke than the other by fixteen pumps of feven 
inches bore and 2\ feet ftroke, and therefore with much 
lefs lofs of power by friftion ; and as the cranks only 
work in one direttion, they work much more pleafantly 
than when there are pumps at both ends of each lever, be- 
caufe in that cafe the ftrain on the cranks, connefting-rods, 
and the fulcrums of the levers, in faft on all the joints, is 
alternately in different direflions, and if there is any ftiake 
or loofenefs in the joints, it produces jerks and ii-regularities. 
By ufing three barrels and triple cranks, the fupply of 
water, forced into the main-pipe, is more equable than when 
four are ufed, though not perfeftly fo. The perpendicular 
motion produced by the arches and chains, is a great advan- 
tage in making the barrels wear equally. 

In order to enable this engine to work as long as poffible 
in each tide, and after the velocity of the motive water is 
abated, it is contrived to adjuft the refiftance to the dimi- 
nifhed power. This is done in the moft fimple manner by 
a fmall cock and pipe in the chamber of each pump-barrel; 
juft above the fuftion-valve from this cock, a rod of com- 
munication rifes up to the ftage to turn it by, and this cock 
being opened will admit air into the barrel when the pifton 
is drawn up, fo that the water of the river will not be drawn 
up into that barrel ; and in confequence, it will become in- 
aftive, and the wheel will be relieved from the load of work- 
ing it. In this way, the load of the engine is adapted to 
the power of the tide at its different periods ; but when all 
the three barrels are thus relieved by opening the air-cocks, 
the motion of that engine becomes a ufelefs loud friftion of 
the piftons and movements ; and to relieve this, the fhaft or 
axis of conneftion between the axis of the trundle and the 
triple crank, is provided with the means of difuniting or 
uniting them whilft in motion, fo that one engine will ftand 
ftill whilft the other is at work. 

The principal dimenfions of this machiae are as follow : 
— The water-wheel is thirty-two feet diameter, meafuring 
to the outfide of the float -boards ; the length of the iloat- 
boards fifteen feet and a half, and their breadth four feet 
and a half ; the number of float -boards twenty-four. At 
each end of the axis is fixed a cog-wheel, fourteen feet dia- 
meter, with eighty cogs : each of thefe turns a trundle of 
twenty-three ftaves, fixed on the axis of the cranks, which 
are triple ; that is, three cranks are formed fide by fide on 
the fame axis, and bent in different direftions, fo as to pro- 
duce a continual aftion. Each crank aftuates a lever or 
working beam eighteen feet long, which is poifed on a ful- 
crum in the middle, and gives motion to the pump-rods by 
an arch-head and iron chains. The pump-barrels are ten 
inches diameter, and the piftons make ftrokes of four feet 
and a half long ; they are forcing-pumps, and three barrels 
are combined together, to throw the water into one main 
pipe, which conveys the water into the town ; the higheft 
elevation to which the water is ever lifted is a hundred and 
twenty feet. The cranks, beams, and pumps, at each fide 
of the wheel, are exaftly fimilar, fo that the wheel aftuates 
fix pumps. 

This machine was erefted, under Mr. Smeaton's direftions, 
in 1767, and worked conftantly for fifty years, when the 
timber-work becoming decayed, it was rebuilt in 1817, with 
caft-iron inftead of wood, and has been lately fet to work. 
The principal proportions of Mr. Smeaton's deCgn have 
been preferved, but the great levers have been fuppreffed, and 
the cranks are placed over th« fame pumps as the former. 

Mr. Smeaton's Pump Machine at Stratford IValer-JWorks. — 
This is fo like the laft, that we (hall only give the principal 
dimenfions, as an example of the beft proportions for a ma- 
chine with a breaft-wheel, the laft being underftiot. The 
water-wheel was fixteen feet diameter and eight feet wide ; 
upon its axis was a cog-wheel of eleven feet and a half dia- 
meter, with feventy-eight cogs, which turned a cog-wheel of 
five feet one inch diameter, with thirty-five cogs. This was 
fixed upon the axis of the cranks, which were three in number, 
and by means of three beams gave motion to three forcing, 
pumps nine inches diameter and two feet and a half length 
of ftroke, lift of the water 84 feet. In addition to the pair of 
cog-wheels juft mentioned, there was another pair, of different 
proportions, fixed clofe to the fides of the others, and by a 
fimple contrivance either pair could be brought into afUon, 
and the other pair would then be difengaged. The fecond 
wheel, which was fixed in the axis of the water-wheel, was 
nine feet eight inches diameter, with fixty-fix cogs, andtte 
wheel on the axis of the cranks which belonged to it had 
forty-feven cogs. The intention of thefe two fcts of wheels 
was to adapt the water-wheel to work equally well when it 
was flooded and impeded in its motion, as when the water was 
low; for when the quick motion was in ufe, the cranks made 
15.6 revolutions per minute, whilft the water-wheel made 
feven revolutions. But when the flow motion was in ufe, 
the cranks would make 15. -i revolutions /i^r minute, whilft 
the water-wheel made eleven. This machine is feven horfes' 

The Pump Machine at Marly, near Paris, being fo much 
celebrated on account of its magnitude and the multiplicity 
of its parts, we fiiall be expefted here to give fome accoimt 
of it, which we have taken from Behdor, and we ftiall fub- 
join a few remarks upon its conftruftion, from which it will 
appear we do not recommend it as a model. 

This machine is fituated between Marly and the village 
La Chauflee. In that place the river Seine is penned up 
partly by the machine and partly by a dam, which keeps up 
the water ; but in order that the navigation may not be in- 
terrupted, a canal has been cut, two leagues above Marly, 
for the paffage of boats and barges. There has been erefted, 
about thirty-five fathoms from ihe machine, a contrivance, 
called an ice-brcaier, to prevent floating pieces of ice or 
timber, which come down the ftream, from damaging the 
machine, and the better to fecure the pen-ftocks, and the 
channels in which the water-wheels move. There is a grate 
of timber to ftop whatever may come through the ice- 

The water is raifed to its deftined height by the force of 
fourteen underftiot water-wheels, which work the pumps at 
three different ftages : firft, one fet of pumps to hft the 
water from the river, to a refervoir placed up the hill two 
hundred and thirteen yards from the river, and at the eleva- 
tion of a hundred and fixty Enghfli feet above the level of 
the Seine. The power of the wheels is conveyed alfo to 
this place by chains, in order to work a fecond fet of pumps, 
which force the water to the fecond refervoir, a hundred 
and eighty-fix feet higher, and therefore three hundred and 
forty-fix feet above the river, and fix hundred and ninety 
yards diftant. At this fpot is a third fet of pumps, to 
throw up the water from the latter to the fummit of a tower 
a hundred and eighty-nine feet higher, and at a diftance of 
one thoufand three hundred and thirty yards from the river 
up the mountain. The whole elevation is rather more than 
five hundred and thirty-five feet above the river. From the 
ciftern in the tower the water is conveyed, by an immenfe 
aqueduft, to the gardens of Marly. 

The breadth of the machine comprehends fourteen water* 



courfes, each (hut hy a (luice or pen-ftock., which can be 
raifed and depreffed by racks, and in each of thefe courfes 
an undeHhot wheel is placed. The fourteen wheels are dif- 
pofed in three lines acrofs the river. In the firft line, which 
is up the aream, there are feven wheels, in the fecond line 
fix, and only one in the third. 

The wheels are thirty feet diameter, and five feet wide, 
and they are all nearly the fame as follow : the ends of the 
axle of eacii wheel go beyond their bearing pieces, and are 
bent into cranks, which make levers of two feet ; the crank 
which is towards the mountain gives motion to a beam or 
lever, which carries four piftons or forcers at each end, to 
work in the barrels of as many forcing-pumps, which as the 
wheel works alternately fuck up the water of the river, and 
drive it up into the firft ciftern. The other crank at the 
oppofite end of the axle gives motion to the chains, which 
go up the hill, to work the pumps in the two elevated 
citlerns. n j • 

Each of the fix wheels on the firft line is conllrufted m 
this manner, to give motion by one of its cranks to an 
engine, confifting of eight forcing-pumps combined toge- 
ther. The engine is aftuated by a lever or beam, from each 
end of which a fquare piece of wood is fufpended, that 
carries and direfts four piftons of forcing-pumps ; the beam 
of the engine is put in motion from the crank of the wheel 
by a beam or leader, which is connefted with the crank of 
the wheel at one end, and with one arm of a regulator or 
bent lever, whilft the other arm of this regulator is united 
by another leader to the extremity of the beam of the 
engine, wluch beam is thus made to vibrate up and down 
and work the pumps. 

Of the fix wheels wc have juft mentioned, there are five 
which, by their oppofite cranks, give motion to the pumps 
in the elevated ciftern of the firft lift. This is effeded by 
means of one vertical beam or lever, and two horizontal 
levers, which are bent, and aftuate the chains that com- 
municate the motion ; the three levers are only to change 
the direftion of the motion of the crank into a proper 
direaion to go up the hill. The fixth wheel, which is the 
firft towards the dam, gives motion to a long chain that 
goes up the hill to work the pumps of the upper ciftern. 
The feventh wheel of the firft line is exclufively applied to 
move a chain, which goes to the firft ciftern, by both its 

The fix wheels of the fecond line are like the five wheels 
in the firft row, /. c. one of the cranks of each works an 
engine of eight pumps, and the other a chain that goes to 
the upper cillern. 

Laftly, the fiiiglc water-wheel, which is on the third 
line by each of its cranks, works an engine of eight forcing- 
pumps fixed in the river, and of itfelf fupplies one conduit- 
pipe of eight inches and a half bore. 

There are then eight engines in the river, and reckoning 
all the chains which go up the hill, they are thirteen in 
number, including the chains that come from the fixth and 
feventh wlieels of the firft line : thefe thirteen chains afcend 
the hrll all together, and arc fufpended at regular intervals 
of twenty feet by levers, to bear them up from touching 
the ground, which by moving on their centre admit of the 
working of the chains. Each chain is double, that is, there 
i« a fecond chain, which is connefted to the oppofite eiulnof 
th» fufpending levers, and each chain ferve« to draw the 
other chain back again after it has made its ftroke. Five 
of thefe double chains are employed to actuate levers, which 
work thirty inverted lift-pumps fituated in a ciftern at the 
firft lift, and which drive the water through two pipes of 
eight and a half inches bore up to the upper lift. The 

other eight double chains go ftraight on to the upper 

The feven chains of the wheels of the firft line, in going 
along, work alfo eight fucking-pumps, placed a little below 
the ciftern of the firft lift, becaufe in that place the water of 
a confiderable fpring is brought by an aquedu<5^, and thefe 
fame chains take up that water a fecond time by forty-nine 
pumps, which are fituated in a feparate ciftern, at the firft 
lift, on a level with the firft ciftern, and force it into the 
upper rcfcrvoir, through two conduit-pipes of eight and a 
half inches diameter, and three others of fix and a half inches 

The water raifed by the feventy-nine pumps in thefe two 
cifterns at the firft lift, difcharges itfelf into a great refer- 
voir at the fecond hft, and thence by two conduit-pipes of 
a foot diameter each, it runs into refervoirs of communica- 
tion, and is diftributed into the fevcral wells or little pump- 
cifterns of the upper ciftern, which all together contain 
eighty-two inverted lift-pumps ; thefe force the water through 
fix conduit-pipes of eight inches and a half diameter up into 
the ciftern, in thetower which anfwers to the aquedufl. Thefe 
eighty-two lift-pumps are worked by the eight great chains 
before mentioned, that go ftraight to the upper ciftern, 
wiihout moving any pumps by the way ; and the fame chains 
work fixtcen fucking-pumps behind the upper ciftern, to 
bring back into the refervoir of the fame ciftern the water 
which leaks out of the fix iron pipes that go to the tower. 

To fum up all the pumps of this intricate machine : 

1 . The eight engines in the river contain fixty-four pumps, 
which fuck and force the water 1 60 feet up five iron pipes of 
eight and a half inches bore, and 213 yards long, up to the 
firft lift. 

2. The two cifterns at the firft lift contain feventy-nine 
lifting-pumps, which raife the water 186 feet, through four 
pipes of eight and a half inches bore, and three pipes of 
fix and a half bore, and 477 yards up to the fecond lift. 

3. The cifterns at the fecond lift contain eighty-two 
lifting-pumps, which raife the water 189 feet through fix 
pipes of eight and a half inches bore, diftancc 640 yards : 
In all 225 forcing-pumps, wliich lift 535 feet and 1330 
yards diftance. To this muft be added ciglit fucking- 
pumps in the river called feeders, which raife water into the 
cifterns at the top of the forcing-pumps, to keep water in 
the pumps, and prevent leakage ; alfo tlie eight others which 
are below the midway cittern ; and laftly, the fixtcen fucking- 
pumps, which we mentioned as placed behind the upper 
ciftern, fo that the machine has in all 257 pumps. 

The bafin of the tower, which receives the water raifed 
from the river, and fupplies the aquedud, is 13^0 yards 
diftant from the river, and 53 J feet above the level: the 
water having run along a ttone aquedufl, which is raifed 
upon thirty-fix arches, is feparated into difterent conduits, 
which lead it to immenfe refervoirs at Marly, and formerly 
conveyed it alfo to Verfailles and Trianon. 

Such is the mechanifm of the machine of Marly. Its 
mean produce in Belidor's time was from 3000 to 4000 
Englifti cubic feet of water per hour : he fays mean pro- 
duce, becaufe under certain favourable circumftanccs it has 
formerly raifed more than 8484 cubic feet per hour. But 
during inundations, or when the Seine is frozen, when the 
water is very low, or when any repairs are making, the 
machine ftops in a great mcafure, if not entirely. 

The annual expences of the machine have been ftated 
formerly at 3300/. fterling, or 9/. per day, including the 
falaries of thofe who fupcrintend it, and the wages of the 
workmen employed, together with repairs, neceffary articles, 
&c. This ^makes about one farthing for every eleven 



cubic feet. Or, taking iato the account the intereil of 
333,000/., the original expenfe of ereftion, which is five 
times as great as the annual expenfe, 1 1 cubic feet, which is 
67 gallons, will coft three half-pence, or at the rate of a 
farthing for 1 1 gallons. 

This is the account of it given by Belidor in his fecond 

Rannequin, the inventor, was an ingenious praftical mecha- 
nic, but no mathematician or philofophcr. In feveral pofi- 
tions, the movincf forces aft unneceflarily obliquely, which oc- 
cafions a great lofs of power, and renders the machine lefs 
effeftual. A great proportion of the whole moving power of 
fonie of the water-wheels is employed in giving a reciprocating 
motion to the fets of rods and chains, which extend from 
the wheels to the ciftern, nearly two-fifths of a mile diftant, 
where they work a fet of pumps. 

As this machine is continually quoted as the moft power- 
ful of all machines, we will compare its power with fome of 
the large fleam-engines in England. The quantity of water 
is (8484 -f- 60 = ) 141 cubic ketper minute x by 535 feet, 
the height to which it is raifed, =: 75649 cubic feet per 
minute lifted one foot high. Divide this by 528 cubic feet, 
which is the quantity that can be lifted one foot per minute, 
by what is called a horfe-power in fteam-engines = 143 
horfe-power ; but as the machine afts by 14 water-wheels, 
each one will be fcarcely lOj horfe-power. The horfe- 
power is one-third greater than the average of horfes, and 
we therefore eftimate that 215 horfes working together, 
would do as much work as tliis machine ever did, or 15 
horfes to each wheel ; but as the horfes could only work 
eight hijurs pjr day, three fcts muft be kept to continue 

M. Montgolfier informs us that the fupply of water to 
the wheels is 138000 cubic feet per minute, and the fall is 
4^ feet ; this gives a power 8|- times as great as the effeft 
produced. Montgolfier found 225 times when he tried it. 

The whole work is now in a very ruinous ftate, and many 
projcfts have been formed for a reftoration of the machine 
on better principles. 

It is probable Rannequin thought his moving force would 
not be fufficient to raife the water to the height of 535 feet 
at once ; and this is agreeable to the praftice of more mo- 
dern engineers. 

If the machinery was conftrufted in call iron, in the fame 
manner as fteam-engines are now made, the force of one 
crank would be more than fufGcient to raife a cylinder of 
water of that altitude, and above eight inches in diameter, 
without any complication ; but the pipes would require very 
great ftrength. This is proved by a machine that has been 
lately erefted at Marly, in place of one of the old water- 

Even according to the original conftruftion, the water 
might be raifed in one jet to the fecond refervoir. This ap- 
pears from two experiments, one made in 1738, and the 
other in 1775. In the firft, M. Camus endeavoured to make 
the water rife in one jet to the tower ; his attempt was not 
attended with fuccefs, but he made the water rife to the 
foot of the tower, which is confiderably higher than the fe- 
cond refervoir. During this experiment the machine was 
fo much ftrained, that it was found neceflary to fecure 
fome parts of it with chains. 

The objeft of the fecond trial, made in 1775, was to 
raife the water at once to the fecond lift, 346 feet. It did 
afcend thither at different times, and in great plenty, but 
the pipes were exceedingly ftrained at the bottom, fo 
that feveral of them burft, and it was neceffary to fufpend 

and recommence the experiment feveral times. This arofe 
from a fault which might eafily hare been remedied ; vim. 
from the age of the tubes and their want of ftrength ; 
therefore it refults from this trial, that the chains which pro- 
ceed from the river to the firft lift might be fuppr^-f^eA, to- 
gether with the firft well itfelf : and this perhaps is all that 
is to be expefted without a complete change in the 

Rules for cakuliifhi^ the D'tmenfiom of Pumps. — The quan- 
tity of water delivered by any pump will be in ihe joint pro- 
portion of the furface or bafe of the pifton and its velocity ; 
for this meafures the capacity of that part of the working 
barrel which the pifton paffes through ; and the fame is true 
of feftor pumps, or rotative pumps : but as pumps with 
ftraight cylindrical barrels are the only kind in general ufe, 
it will be fufficient to give the rule for calculating the con- 
tent of a cylinder, which is fimply to multiply the area of 
the bafe by the length ; thus, take the diameter of the barrel 
in inches, and the length of the ftroke in feet. 

Square the diameter in inches, and divide by 1 83.3 : tniilti- ■ 
ply this by the length of the flrole in feet, and it gives the con- 
tent rf tin cylinder in cubic feet. 

Example — How many cubic feet of water will be raifed 
in an hour by a pump 85 inches diameter, and 3^ feet 
ftroke, which makes 18 ftrokes/i^r minute ? 

Diameter 8.5 inches ;< 8.5 = 72.25 circular inches : di- 
vide it by 183.3, ^bich is the number of circular inches in 
a fquare foot, and it gives .394 fquare feet for the area of 
the barrel x 3.5 feet in length = 1.379 cubic feet; the 
content of the barrel x 18 ftrokes^cr minute = 24.822 
cubic feet of water raifed ^.r minute x 60 minutes = 1489 
cubic feet per liour. 

If it is required to know the quantity which a pura,p will 
raife in ale gallons, it is obtained by the following rule : 
take the diameter of the barrel in inches, and the length of 
the ftroke in feet. 

Square the diameter in inches; multiply by the length infect, 
and divide by 30. 

This fhould give the content of the barrel in ale gallons 
of 282 cubic inches each ; but the rule is not perfeftly cor- 
rect, for it affumes the gallon to be 282^. 

Example of the fame Pump as above. — The fquare of the 
diameter is 72.25 x 3.5 feet in length = 252.875 — 30=: 
8.429 ale gallons for the content of the barrel. The 
true meafure in this cafe is 8.45 gallons, which is very 

To find the force requifite to work any pump, take the 
diameter of the barrel in inches, and the perpendicular height 
of the column of water in feet. 

Square the diameter in inches ; multiply by .34 decimal, and 
multiply by the height of the column in feet. 

This gives the force in pounds avoirdupois. It is ufual 
to add one-fifth to this weight, on account of friftion and 

Example. — Suppofe the above pump lifts the water 64 
feet in the whole, what force will it take to draw up the 
pifton ? 

The fquare of the diameter is 72.25 X .34lb8. = 
24.565 lbs., which is the weight of one foot high of the 
column X 64 feet = 1572 lbs., the weight of the whole 
column. Add ^th of this, i<iz, 314 lbs. _-; T8S61b8. the 
weight required to draw up the pifton and give it a proper 

In conftrufting pumps, care muft be taken to avoid all 

unneceffary contraftions in the valves or pipes which convey 

the water. If the water-way is too fmall, the water will 

H be 


be greatly refilled in its paffage tlirough fuch contrac- 
lions ; and this is called by the workmen wire-drawing the 

The velocity of the water in the conduit-pipe, and in its 
paffage through every valve, will be greater or Icfs than the 
velocity of the pifton, in the fame proportion that the area of 
t)ie pifton or working barrel is greater or Icfs than the area 
of the pafPage of the valve. For whatever quantity of 
water paflfes through any feAion of the working barrel in a 
fecond, the fame quantity muft go through any one of the 
paffages : this enables us to modify the velocity of the water 
as we pleafe, and we can increafe it to any degree at the 
place of delivery, by diminifhing the aperture through 
which it paffes, provided we apply fufficicnt force to the 
pidon. This is the cafe in the engine for extinguifhing 
fires ; but no fuch increafe of velocity muft be fuftVred in 
pumps which arc required to raife the greateft quantity of 
water with a given power ; becaufe the power required to 
force the water with a great velocity is very confidcrable, 
and the velocity fo obtained adds nothing to the mechanical 
efFed which is produced. The refiftance arifes from a two- 
fold cnnfe ; vix. the friftion of the water againft the fides 
of thi- paftage, and ft ill more from the refiftance which 
water oppofes to any fuddcn change of figure ; for though 
water is a perfeft fluid, and will readily accommodate itfelf 
to any change of figure by its own gravity, yet, it requires 
fome time to make I'uch change ; and if we force it to 
change its figure in lefs time than it naturally would, it re- 
quires mechanical power to do fo, juft the fame as to 

comprefs a mats of clay, or other foft and non-elaftic 

Ill praAice, the velocity with which the pifton of the 
pump moves, determines the fize of the fmalleft paflage 
through wliich the water can pafs witliout unneceftary re- 
fiftance. Few pumps move with a greater velocity than 80 
or 100 feet per minute ; and we think the area of the nar- 
roweft paffages and pipes (hould bear fuch a proportion to 
the area of the barrel, that the water will never be urged 
with a greater velocity than three feet per fecond, or 180 
feet per minute, if the power required to move the pump is 
an objeA. In general, this will be accompfiflied by making 
the area of the fmalleft opening equal to half the area of the 
barrel ; or if the diameter of the barrel is divided into 10 
parts, the diamotcr of the leaft opening fliould be 7 of thofe 
parts. If the pump moves flower, then the paffages may bear 
a fmaller proportion. The pumps which have folid piftons 
arc preferable, becaufe the valves can be made of any fize 
which is defired ; but when a valve is made in the pifton, 
its fize is neceffarily limited to lefs than we have recom- 

EJltmatc of the Strength of Men to raife Water. — Various 
authors have ftated the mean force of a man fo widely dif- 
ferent, that the ftudent is perplexed which to choofe. The 
following table contains feveral of thefe ftatements, wliich 
we have reduced to one common denomination ; viz. the 
number of pounds avoirdupois, or the number of cubic 
feet of water which a man can raife up in one minute to the 
height of one foot. 


I'omids Avoinlu- 

pois XfMeA linn 
Foot ptr Minnir. 

C'ub'u- Feci of 
Water r-.ifra one 
Fool per Minute. 

Duration of tl.e W . u . 

Hachette . - . - 
Amontons . - - - 
Euler - - . - 

Smeaton . . , . 

Bemouilli . . - - 
Schulze • - . . 

Defagutiers . - - - 
Emerfon .... 

Dr. Robinfon . • - 

Average of all thefe - - - 


r 3668 

■: 3750 
I 3859 


{ 503« 

1 6648 




58-7 7 
60. \ 
61.7 3 


ICO. 8 


Working 10 hours y>fr day. 

Working during 8 hours in 24. 
For 8 hours. 

For 10 hours. 

fA feeble old man, working 8 or 10 
hours per day, a pump without fric- 
(, tion.' 

f A young man weighing 135 lbs.: 10 
\ hours /cr day. 

True ftandard - - - 3750 

60. Working 10 hours /x-r day. 

It is not difficult to account for thefe great diff"erencef., 
when we confider how the mufcular force varies in dift^erent 
individuals, and alfo the power of enduring fatigue. The 
only means of afccrtaining the mean force of a man is to take 
the fum total of the work executed by a number of men 
afting for a great length of time. This was repeatedly 
done by Mr. Smeaton, on a very large fcale, and with fo 
very little variation, that we can very confidently recom- 
mend engineers to calculate a man's force at 60 cubic feet, 
or 3750 lbs., raifed one foot per minute : as this is juft one 
cubic foot per fecond, it will eafily be fixed in the memory. 
Defaguliers' cRimate of one hogftiead raifed ten feet b"gh per 

minute, is very frequently ufed, and is 5500 lbs. railed one 
foot per minirte, but it is too great for a mean ; and Defagu- 
liers himfelf called it the maximum, which no machine can 

When a machine is to be turned by the force of a man 
turning a winch or handle, the handle ought not to be 
longer than from 12 to 16 inches; nor ftiould it be calcu- 
lated to mnke more than 30 turns per minute ; and when 
moving with this velocity, it (hould not require a greater 
force than 1 6 J lbs. prcfl'urc ujjon the handle ; or a man will 
not be able to move it without greater fatigue than he can 
endure for a day's work. If the handle is required to move 



flower, for iiiftance 20 turns /^r minute, tlien the load may The Force of Horfes to raife Water. This we find a> 

be increafed in proportion ; vir.. to 255 lbs., and this will be varioufly ftated by different authors as the force of men. 

!efs fatiguing. 


Pounds Avoirdu- 
puis raifed one 
Kout/Jfr Minute. 

Cubic Feet of 
Water raifed one 
Foot per Minute. 

Duration of the Work. 

Hachette's eftimate that a horfe is equal! 

to 7 men - - - - -J 

Fenwick ------ 

Gregory ------ 



Smeaton's 2 horfe machine, with anl 

Archimedes' fcrew - - -j" 
Smeaton's 4 horfe machine to work al 

flafh- wheel J 

Smeaton's ftandard - . - . 
Defaguliers' eftimate that a horfe is 1 

equal to 5 men - - - - j 

Smeaton's experiment on drawing coals |^ 
with 2 horfes - - - •\ 

Meffrs. Boulton and Watt's horfe -power' 
in fteam-engines - - - -\ 









211. 2 






Working 9 hours per day. 

Working 9 hours per day, light work. 
Working 8 hours per day. 

r Working i^\ hours per day, 4 horfes 
were kept in order to work for 

(, 9 hours per day. 

fThe ftrongeft horfes, fuch as are ufed 
in London, cannot work at this rate 

(, throughout the day. 



f Working 8 hours per day, nearly equal 
\ to 6 men. 

In this, as in the former inftance, we feel inclined to give 
the preference to Mr. Smeaton's eftimate, both from his 
fuperior experience and accuracy, and alfo becaufe by his 
MS. papers, we are informed of the particulars of his ex- 
periments. He found, from examining the accounts of a 
colliery, that each horfe drew 27720 pounds one foot per 
minute ; but as they could only continue to work at that 
rate for \\ hours per day, Mr. Smeaton fixed his ftandard 
at 250 hogftieads per hour raifed ten feet, which is equal to 
22,916 pounds, raifed one foot high. Still we find in two 
of his machines, of which we have already given the parti- 
culars, the performance fell rather (hort : we have, there- 
fore, chofen to recommend 352 cubic feet of water, or 
22,000 pounds per minute raifed one foot high, as a ftandard 
for a horfe's force, when he works 8 hours per day, and 
moves with a velocity of 2^ miles ^fr hour. This is fettled 
by univerfal confent as the moft preper pace for a horfe to 
walk ; and he will in that cafe draw juft lOO pounds, which 
is an eafy number to remember. 

The eftimate of Defaguliers we confider as the maximum 
of a horfe's power ; for the horfe-power of Meffrs. Boulten 
and Watt is only ufed as a meafure of the force of their 
fieam-engines. See that article. 

In applying horfes to work machines, the circular traft 
in which they walk ftiould be as large as poffible, 
that the horfes may turn round in the curcle with little 
inconvenience. Few cafes will admit of a walk of more 
than 30 feet diameter ; and in proportion as this is di- 
minifhed, the horfe lofes feme of his power. No horfe-walk 
(hould be made of lefs than 20 feet diameter, if he is re- 
quired to atft with any confiderable force. Whei) this fize 
cannot be obtained, we are of opinion that the horfe woulcl 
work to a gjreater advantage by walking within a large per- 
pendicular wheel, like tkofe wkeels ufed for cranes. 

It muft be remembered, that the horfe (hould always 
move with a velocity of 2\ miles /ifr hour, or 220 feet per 
minute ; and, therefore, the number of turns which he will 
make in a minute muft be proportioned to the fize of the 
track in which he works. 

Number of Turns 

Diameter of the 
Horfe's Track. 


per Minute, when 
the Horfe walks 

30 feet. 

94 feet. 

















The machine which is to raife the water fhould be fo 
connefted with the principal wheel which the horfe turns, 
that it wrill move with the proper velocity, when the horfe- 
wheel turns at the rate above fpecified. The velocity 
proper for moft machines is mentioned in the defcription 
of each. 

Water-Wheeh applied to raife Water. — The circumference 
of a water-wheel will work to the greateft advantage, when 
it moves with a velocity of from 3 to 4 feet per fecond, or 
from 180 to 240 feet per minute. A very proper velocity 
for a water-wheel is to make it the fame as the horfes, by 
the above table ; and we have, therefore, added the velocities 
for fgaailer diameters. 

H 2 





Turns per Mmu 


1 8 feet. 

56.4 feet. 














Few macliiiies, with pumps worked by a watcr-wliccl, 
will raife more water to a given height in any time, than 
amounts to one-third the mechanical effeft of the quantity of 
water employed to work it ; that is, confidering the dif- 
ftrences of the heights to which the water is raifed, and the 
height of the fall, and reducing them both to an equably, 
the quantity of water raifed will never exceed half of the 

quantity which falls. The other half is loft in friftion and 
leakage, and in overcoming the inerliti of the parts of the 

Prejfure engines are thofe machines which give motion to 
the pillon of a pump, by the force of a column of 
water aAing in a cylinder or barrel, fimilar to that of 
the pump. (See the article PREssuiiE-£n_f;nf. ) It was 
orriittcd in that article, that M. Belidor invented a ma- 
chine, which may be confidercd as the firll which was 
perfect, and was indeed the model for that made by 
Mr. Smeaton. See Architetflure Hydraulique, vol. ii. 
p. 240. 

M. Baillet made obfervations upon feveral machines of 
this kind in the mines of Hungary, from which it appears 
that the mechanical effcft produced, is only four-tenths of 
the mechanical efFetfl of the firft power. 


of Water to work 

the Machine. 

Diaineicr of the 

Quantity of Water 
expended in 
24 Hours. 

Height to wliieh 
the Water is raifed. 

Qusntivy i.f Water 
raifed in 24 Hours. 

ftnJ the Caufe. 

French Metres. 




Cul.ic Metres. 






Cubic Metres. 





0.4 mean. 

The French metre is equal to 3.281 Engliih feet, and the 
cubic metre is 35-3198 cubic feet Englifh. 

Poiuer of the largejl Sleam-Engincs to raife Water. — The 
moft powerful machine in exiftcnce is the Iteam-engine, on 
Mr. Watt's principle, called Stoddart's engine, at the 
United Mine in Cornwall. Three other engines of equal 
dimenfions are employed to drain the mine, but only this 
one is loaded fo as to exert its utmoft force. The lleam 
cyhnder is 63 inches diameter, and afts double ; that is, it 
operates to raife water equally in the afccnt or dofcciit of 
the pifton. The weight of water in the pumps is 82,000 
pounds, and with this load it makes 6i double Rrokes per 
minute of 7} feet each ; or, it gives to the load i oof feet 
motion per minute. 

Multiply 82,000 pounds by looj feet, and it gives 
8,261,500 pounds per minute lifted one foot high: divide 
this by 33,000 pounds, which is called the horfe -power, and 
it gives 250I horfe-power for the afting force of the engine. 
Again, divide 8,261,500 pounds by 62^ pounds, the weight 
of a cubic foot of water, and we find this engine is capable 
of raifing 1 32, 1 84 cubic feet of water per minute to a height 
of one foot. This is not one of the beft engines with re- 
fpeft to fuel, and it burns 3I5 pounds of coal to raife this 

The whole power employed to drain the United Mine is 

as follows : 


Stoddart's engine, 63 inch cylinder, double aAing 250^ 

William's engine, 65 inch cyhnder, do. 200 

Sim's engine, 63 inch cylindet, do. 185 

Poldorey's engine, 63 inch cyliiid<.r, do. 1 96 

Total - 831 1 

Here we have a fingle machine of nearly double the 
power of the famous machine at Marly, which is in fa6t 
compofcd of fourteen machines, working in concert for a 
common objeft ; and fo do the four engines in the mine, 
whicji amount to 831 3 horfe-power, without reckoning the 
engines employed to draw up the ore. 

The engines at feveral other mines in Cornwall are of 
immenfc power. We will ftate two. 

The mine called Wheal Alfred has four engines : a 
G^ inch double engine, which is lightly loaded, and only 
exerts So horfe-power ; a fingle aAing engine of 66 inch, 
and 60 horfe-power ; and two others of 64 and 60 inch, to 51 and 54 horfe-power : — in the whole, 245 horfe- 
power to drain one mine. 

The Dolcoath mine has three engines : a double engine 
of 63 inch cylinder, and 132 horfe-power; a fingle engine 
of 63 inch, and 45 horfe-power ; and a fmaller fingle engine 
of 20 horfe-power : — in all, 197 horfe-power to drain the 

It will be obferved above, that the power of the different 
engines is not in proportion to the dimenfions of the cylin- 
ders : this is bccaiife the prcffure upon each fquarc inch of 
the pifton varies in different engines from 7 to 20 pounds. 
But cuftom has eftablifhcd, that certain fizes of cylinders 
will be equal to a certain number of horfes' power, as is 
flicwn by the following table.- 

The fteani in the boiler is fuppofed to be kept within the 
limits of from 2 to 4 lbs. prcffure on each fquare inch more 
than the atmofphere ; and in that cafe the cyhnders of the 
diameters marked in the Tabic will have very nearly the 
powers afTigned to them. 

A Table 


c So 

M -< N W^ t(- 

-in -IN 
O OS to O V3 
lo loO t^ t^ 


tooo tooo to 
00 00 Ov ON o 

-IN -IN 
00 to On 'j- Ov 

O >- - N ("l 

■* Ov to t- >« 

>O00 Tj-OO -*■ 

lo loo vo r^ 


O r^ to *n -^ 

O l-~>0 O to 
- N -^ lo 

vo vo t-~ t^ t-- 
vo r^oo ON O 

" N to ^ lO 

00 onO ■+ t) 

O t--oo o 

O t- OvO 00 
« « t< to •* 
to to to to CO 

3 "S 1 i; 

c5 i^ CO N d 

q oc q t^ i^ 
6 6\ 6\co CO 

to q 00 vq ■+ 
50 00 t^ t^ r^ 

N - q ONCO 

t^ r^ t^>o NO 

i~-vq lo ■* to 

vo vo vo NO vo 

tj ►; M O O 

O O O VO vo 

il J 1 
.i's 2 



O o o o 

o 8 8 8 8. 

too fr, CnO 

o o o o o 
o o o o o 
q, o o q o 
O vo tJcc -J- 

to OvVO tl ON 
to to tJ- U-, lo 

O o o o 

8 8 8 8 8 

O" O" N CO ■>? 
VO N CN lo N 

VO r- t^oc Cv 

O O O O 

8. 8 8 8 § 

onvo t-i CO 4- 

Ov Vo N DO lo 

Ov q « « t^ 

O o o o 

8, 8 8 8 8 

ovo tToc" -t- 

t) CO lo - oo 
to to •J vo to 

o o o o 
o o o o o 
q q q o o 
do" tSOO •.?■ 

lo - 00 -;J- - 

vq t;- t^oo ON 

^ 3 

00 O « 00 ■<<- 

vo N 00 -i- 
00 to c\ -^ O 
M to to -^ to 

LoO t^OG 0\ 

VO M 00 T^ 

VO - r^ N 00 
love vo t^ r- 

o -- 5 t?. ^ 

oo tios -1- 

^ Ov lo O O 

00 00 ON q q 
•ovo r^ On o 
I- -< ». ^- r< 

oo IS 00 ^ 
t< t~- tooo ^ 

" tT t^ T? uP, 

O O t4 CO Tj- 
O "o- o IS 

■^ -^ lo LoO 

O t^co On c5" 





to Tt- l^ N L^ 

00 00 00 Cn O 

vo vo CO o o\ 

OV t^ ON Ov ON 

o o o o 
o o o o o 

O O o o o" 


O O O o 

loioio lo lo 

o o o o o 

3 1 
S 5P 

vo CC >^ O 

Cv On Ov Cv Cv 

o o o o 
o o o o o 

^ 'J- ■* ^CO 
O O O O O 

00 CO 00 00 o 

O O O O - 

N N t) N N 

o o o 

(S is N n IS 

II t| 

O N -+- - r- 

Lr,Tt- to tON 

-1- rf t) t) 1-1 
M t) N ts N 


r»- t^ r^ t-^O 

O O O O lo 

lo lo lo vo -i- 

„h -|C< -IC< 
■- N N to to 

-J- ^ ■* -t- ^ 

vo vo lo vo vo 



O O O o r- 


r-> r- r^ f^ r^ 


s = 


0\ O r- t-~oc 
1-1 to r- O to 

00 N r-vo O 

— vo vovo O 
r^ O covo O 

- N N t< to 

O O 

o too c^ t) 

too Ov N o 
to to to ^ Tj- 

r--0 tooo 

ONt^ O N N 

CO - loOO o 

-^ lO >0 LOO 

O to O CO to 
'^O CO On rt- 
tOO Ov N lo 

o o o r^ t^ 

r^ - vo o -1- 
vo r^co o « 

CO - -l-oo - 
r^c» CO oo On 

_ N to q On 
r^ r^ t^ t^vo 

t^ t^ r- r^ !>- 


to to Th lovo 

t-- A t^ t^ t^ 

NO to ^ t^O 
t-^ t-* t--. t^ t^ 

vq vq r~- t>. t^ 
r-- t-* t^ t^ c^ 

Vo «-^ Ov On 
J~- i> t^ t-~ r^ 

r^ t^ i>- c^ t^ 



z ~ >S 1 "^ 

q rh l/^ ^ Ov 
00 Avo >o tJ- 
r< t< r< N N 

vtn O t-- to On 
ri- 4- to tJ-. r! 

NO •+ tj CNvq 

•o to tj q ON 

N tl M N « 

oo t^vq Vo -t- 
6 6 6 6 6 

N M r) IS t) 

•>i- to to to IS 

6 6 6 6 6 

tS <S N t) tS 

s 11 

00 thVD N Os 
N VO O lo On 

loOO N to M 
N N to to •>*- 

N to N CN lo 

lo On tovc o 
th -^ to uoO 

lo ti - o -^ 
T)-oo p» lo On 
O o r^ i-~ r- 

IS CnO to Ov 
too o ^ r- 
so CO On Ov On 

O Vo — O M 
t^ lo On to r^ 
o 5 " - 

O «OVO OS 0\ 
vd 00 « to >o 


r~ N vq t^ q 

i>- c3n ^ to 

i-i 1- N t-1 N 

q « ■- OnOO 

■4- vovo v6 lA- 

N r) M tl N 

I>.lO to 00 
oo cJv 6 - " 
tJ t< to to to 

vq to r-- to 

t3 tJ; 4 'i- lo 

to to to to to 

_ vq to 00 
vo vo r^od 00 
CO to CO to en 




-let « N to Ti- 

•OVO 1--CO Ov 

O -' t^ to tj- 

>oO t~.oo On 

M -1 M M M 

O "< IS to ■M- 
N N N N N 

loO i>.oo Ov B 

3 c 

IH N Tj-iO 00 

t< Thvo CO 

O tJ ^O oo 


to to to to to 

O IS -to 00 

f> -+0 oo 
lo vo lo lo vo 



m J 




r~ W1 Ov •" t- 

«0 t^ — NO 03 

o O - - - 

f4 N N N N 


•+00 N - I-- 

CO r< NO NO 
0: - <o + 
t< to to to to 

to ■+ loOC 10 
NO I^OC ^ - 
to CO to CO •+ 

On .1 NO to On 
w •+ *o 1^00 
•<»-■+■+■+ ^ 


Cs to 
- tox 
to to to 




rJ-VO 00 M ■* 

NO O M «^ f- 
O — »< <^ T<s 
•4- ■<*•■*••+ ■<*- 

00 NO Tj- N Irs 
•+ r-- N ITS 
•4- <<Mr> UN trs 

t-~ ITN M to 

r~ roNO On 


NO 00 t- 
N ♦ r~ On to 
f~ r~ t~- t~oo 

00 10 coso On 
>ooo - -1- t~ 

00 00 On ON ON 

On NO 
- - 


0\ C\ O\00 CO 

oo r^ r^ r^vc 

NO NC NO K-\ Vn 

1^ Lrs ly> ly^ lo 

to LO 10 >0 so 

to to to 

Vr> 10 UN Ll-I Ny^ 

lO >0 Vrs LO to 

to to to 



o o o o o 

Q O O O O 

q q q q q 
o vo N CO ■4- 
» •* - r^ ■* 
q\ q - - N 

« N N N N 

Q O O O Q 
O O O O 5 
O O O 
CJVO Noo" •+ 
- t^ •<»• O t- 
ro «*^ -i- t^ t^ 


o_ q q q o_ 
•+ iP, cT N^ cf 
r- c<-j 

NO 00 On - wi 

M N N to wi 


q q q q q 

NO C? >^ (3 CO 

NO to On NO to 
toNO r~. !> - 

to to to CO '^ 


9. 9 9. 9, 9. 

NO 00 Cj NO to 
toQC M CO 00 
to -1-NC C~- On 
•+ -f ^ 'f'? 

Q Q 

q q q q q 

•+ - r~ t^ r-. 

1 '^ "t^"^ 

q q 
r^ CJso 
CO On 

no" no" NO 


O «5 IS 30 ■+ 
00 fO O •*• O 

vq t^ r--=G q, 

>r « «»i •* »^ 

O VO N CO -1- 

sc — r^ N oc 
q. q q - - 
vooo (> o - 

tn W5 CO •+ Tj- 


-+00 N NO 
M 00 ITN "- CC 

N •+ t^ 0* N 

^ .j- •+ U-, tn 


-1-00 tS NO N 

•+ q t^ CO i*N 

loOO toNO 
»0 loNO NO NO 

NO CO 00 
On N NO r» 

NOCO Oi 10 t^ 
^ - CONO (^ 

NO t^ r^ r~ t- 

00 00 00 NO 'J- 

NO + - 00 

to NO 00 On 
t<" to t^ to 

00 00 00 On On 



'^rS. 9> 

Cs to — 

OnO - 


'» "B 

c ^ 


i ^ 

> a. 

o o o o o 

O O O o 

•+M N M N 

On On On Cn On 
On On 0. On On 

Os On OnOO 00 

On On On OS OS 

CO «^ r^ r^NO 
On On On Os Os 


so No to 



O O O O 

o'o o o o 

N N N « « 

00 •«»-•+■+ •+ 
M N M N N 

00 00 00 00 00 

On On OS On On 

to r~ I-.NC NO 


NO to to Th CO 

Os Os On On On 

« - 

Os OS Cs 

'*-^'*-^ Tt- 


to « N N N 

- t^TT 

*o 'K'S 

On On OS 

« ^ t> 

t^ t^ t- t^ r- 

00 00 so CO DO 

03 00 00 00 00 

0\ On On On ON 


^ On On On On 






o = c 

oo N r- « vo 

■*- t^ O r<ivo 
6<(^6 O 6 

O fo O CO »<> 

1 "t "7: °. '^ 

N 00 t^NO 

On ij-i uwc t^ 
NO r~. 10 to - 
N to •+■ loNO 

10 coNO 

q. to - q q 

NO 00 1^ ~ 

NO CO CO •+ 
NO - !•< 

qNq «o ^ •+ 
cT c< CO •+ 10 
C« N c< C4 N 

loNO C^ 00 NO 

NO -+ On to to 
1 'i 9. 1 't 

SO r^oo S. 6 
« f* N ts to 

•+ 10 « 
00 to t< 
•+ toOO 



OO 30 CO O ON 
ti t^ t^ r- t- 

00 06 06 00 00 

r< « N tj 
06 00 00 00 00 

1 T T'T T 

00 00 00 00 00 

00 00 00 00 00 

t~ t^ t^OO 00 

00 00 00 00 CO 

On ON q 
00 00 On 





- - q o o 
6 6 6 6 6 

0\ On Onoo 00 
On On OS 0\ On 

00 t~. t^NO NO 

On On On On ON 

UN>n>^>^ VN 

0\ On On On Os 



CO CO to f« M 

On On On On On 

N « fj 


C 4, • 

c 't-oo N so 

I-) N M t<> r<> 

NO <»HM "> -t- 

00 wi r~ ■<*• 
m rl- -il- Lri lo 

-t* to M to 
On i^ 1--NO NO 
lr^^O r-00 On 

CO 10 M to 
•+•«--*- ^NO 
- c< to -t- 

r« c< ■+ t^ N 
10 •+ CO r« M 
w-.N» r^oo OS 

OS t-~ r-00 - 

- N to ■♦ 

M 00 - 
CO ■>*- I-. 


CO CO •<*- 

1 J 

M 00 ■* _ VO 

(5> 6> 6 - - 

«o W+ •* •* 

N rl fO wi ■4- 

M VtN««. 
»^NO t^«B 6 

•* ^■+-+>o 

- C* cj> 4-NO 

Aoo OS 6 - 
W, UskoNO NO 

rj to ■4- toNO 

so NO NO NO so 

00 6 C^ 

NO t- r-. 


O » N m Tt- 

l«NO r>.00 On 

H« -in 

t4 "Nl-. 

•<^ + •+ •+ iTN 

t^ No r^ Q to 

No NO 10 NO NO 

NO 00 r< >o 
NO NO r^ t^ c- 

00 CONO On 
i^ao ec 00 00 

•*• NO 

» ■ 

^ a 

vo vo vo >0 >o 

r» •♦NO 00 
r^ t^ r~ t~ c- 

"^ >^ 
00 00 On On8 

10 "^ Nfl 
- - M N 

NVO ro- 
coco •♦♦ W> 

so - NO t« 00 
toso NO t~ r^ 




This Table is formed from'obfervations of a great number 
of engines of different powers, and making the intermediate 
iizes to correfpond to the fame law of increafe. Thus, a 
twenty-horfe engine is always made with a cylinder of 24 
inches diameter, which is allowing 22.6 fquare inches of the 
pifton's furface for each horfe-power ; but larger engines have 
a lefs allowance; an eighty-horfe engine has 19.8 fquare 
inches to each horfe-power, and fmall engines have a much 
greater allowance ; a ten-horfe engine having 245, and a 
one-horfe, 28 fquare inches. This difference is to compen- 
fate for the numerous difadvantages which always attend 
fmall machines. 

The proper length of the ftroke for different engines is 
not at all fettled. Mr. Watt's firft engines were made 
much longer than this Table, but of late years they have been 
made fhorter, and without any adequate reafon which we can 
perceive ; for it muft. be an advantage to a machine to make 
as few reciprocations as is confillent with a praflicable 
length of cylinder. Thefe differences in the length of ftroke 
do not affefl the calculation of powers, becaufe if the 
length of the ftroke is altered, the number per minute is alfo 
changed, and the velocity of thepifton is the fame ; atleaft 
it will be always nearly the fame as the Table for thofe en- 
gines which work a crank and fly-wheel. But it muft be ob- 
ferved that thefe engines move with a greater celerity than the 
engines for pumping water, becaufe it is neceffary to accu- 
mulate a confiderable velocity in the fly-vs'heel, or it muft be 
immenfcly heavy if the pifton was to move fo flowly as the 
pumping engine generally does. 

It is ufual with engine-makers to calculate the velocity 
of the piftons of engines at 220 ii%\. per minute ; but we 
have rarely found them to come up to this in praftice, and 
have therefore calculated them at lefs. In tlie Table, the 
preffure upon each fquare inch of the furface of the fteam- 
pifton is in proportion to the velocities there marked ; and 
if the velocities are found lefs than the Table, as is the cafe 
with engines for pumping, then the load upon each inch of 
the pifton muft be increafed in proportion, or elfe the power 
of the engine will be different, although the cyhnder re- 
mains the fame. 

For inftance, the engine at the Birmingham canal, 
mentioned in the article STEAM-£n^;nf, had a twenty- 
inch cylinder ; and being a fingle engine, fhould, by our 
Table, be rather more than feven horfes power. How does 
this agree ? The weight raifed/)fr hour to one foot high was 
calculated, in the article Steam-^hj^/w, at 13,961,805 lbs.; 
which divided by 60 gives 232.697 lbs. per minute : divide 
this by 33, coo, the horfe-power, and we have a feven- 
horfe power ; fo far it agrees with the Table. But the 
preffure on each fquare inch of the pifton was 1 1.7 lbs., and 
the Table fays the preffure (hould be 7.1 lbs. This dif- 
ference is reconciled by the differences of the velocities ; for 
the pifton of the Birmingham engine moved 63:5 feet per 
minute, and the velocity in our Table for a fingle engine is 
98 feet : now as 1 1.7 lbs. is to 7.1 lbs., fo is 98 feet to 59I 
feet, inftead of 63:5 ; the difference is very fmall, and may 
be thus accounted for. The Birmingham engine, although 
feven horfes power, had only a twenty-inch cylinder, yet, 
according to our Table, it Ihouldbe 20.6 ; its pifton there- 
fore required to move rather quicker, in order to make an 
equal produce. Thus, the area of a twenty-inch cylinder is 
314 fquare inches ; and of a cylinder 20.6 diameter, it is 332 
fquare inches: now as 314 fquare inches is to 332 fquare 
inches, fo is 59^ feet per minute to 63 feet per minute, inftead 
of 63^, which the engine aftually moved. 

The allowance for fuel in this Table is as fmall as it will 
ever be found to be in aftual pradlice ; the jonfumption of 

fuel is not in direft proportion to the power of the engine, 
becaufe fmall engines lofe more heat, and have more friftion 
in proportion than large ones, and the reciprocations of the 
motion are more frequent. We have taken the effeft of the 
twenty-horfe engine at twenty millions of pounds of water 
per minute, raifed one foot with each buftiel of coals weigh- 
mg 84 lbs. ; this makes the confumption of fuch an engine 
very near two bufliels per hour ; an eight-horfe burns one 
bufhel. We have alfo taken the performance of the engine 
of 100 horfes at 30 millions, and made all the intermediate 
iizes by a regular law of increafe ; the refult agrees fo well 
with feveral engines which we have obferved, that we con- 
fidered the Table as very correft. The quantities of coal 
are the fmalleft ; fcarcely any engines will do with lefs fuel 
when they are working with their full load ; but many en- 
gines will require more. Engines will be conftantly found 
which are of the dimcnfions marked in our Table, and are 
called fo many horfe-power, although they are working with 
either a greater or leffer power than the Table expreffes ; 
in fuch caies, allowance of fuel muft be altered in proportion. 

We have now gone through the defcription of thofe ma- 
chines for raifmg water which are aftuated by the mechani- 
cal force of animals, or water or fteam afting externally by 
means of levers and other conncftmg mechanifm ; but there 
are fome machines in whicli a current or a column of water 
is made to operate within clofe veffels, and raife water to a 
confiderable height : thefe are the Chremnitz fountain, the 
fypho interruptus, and the hydrauhc ram. Thefe are pnoft 
admirable machines, particularly the laft, becaufe they are 
fo fimple, and having fcarcely any moving parts, are not 
liable to decay and injury ; and they do not wafte the motive 
power in unneceffary friftion and refiftance. 

The original fteam-engines of the marquis of Worcefter 
and Savery, which are all of this clafs, are fully defcribed 
under the article SrEAM-Engirie. The wafte of fuel in thefe 
engines is fo great, that they fall very far below other en- 
gines. We have mentioned the engine made by Mr. Kier, 
which by a calculation will be found to raife only af milLons 
of pounds of water one foot high witli each bulhel of coals, 
and the power of the engine is 2|- horfes. An engine of the 
fame kind, of five horfes power, which Mr. Smeaton calcu- 
lated raifed 5 1 miUions, End this is perhaps the utmoft of this 
kind of engines. Another engine of 2f horfe-power, raifed 
55 millions. The beft engine on Newcomcn's principle will 
raife 10 millions ; Mr. Watt's 30 millions; and Mr. Woolf's 
50 miUions. From this ftatcment, it is clear that the expence 
of fuel in Savery 's engines is fo great as to counterbalance 
any advantages ai-ifing from their iimphcity. 

Tie Chremnitz Machine. — In this a column of water, de- 
fcending from an elevated refervoir, is made to raife up an- 
other column of water from a confiderable depth, and air is 
introduced as the medium for communicating the preffure of 
the motive column to that column which is to be raifed. 
This machine is not a new invention ; its principle is fully 
defcribed in the Italian book, "Le Machine," by Brancas 
of Rome, 1629. A machine at Chremnitz, in Hungary, 
is fo celebrated as to have given a name to this invention 
from its fize, and the moft extraordinary formation of 
ice and fnow by the working of it, befides that it is the 
only one of the kind which had been applied to large works. 
An account was given to the Royal Academy at Paris by 
their correfpondent M. Jars, which is inferted in their me- 
moirs for the year 1768 ; and Dr. Wolfe has alfo defcribed 
it. The machine was executed by father Hell, a profeffor 
of aftronomy at Vienna, in the year 1 755 ; it is ufed to raife 
the water in a ftiaft named Amalie, in the mines at Schrem- 
nitz, or Chremnitz, in Hungary : Jig, 14. Plate Wa- 


Ur-v;srks, is a (ketch of this machine, in which the pipes 
are not drawn in the proportion of their lenjjths, but are 
contrafted to the fpace of the defign. O is a wooden 
trough, placed in the middle of the mountain, 143 feet 
above the place, K, where the water drains olf ; this water 
is conveyed from the mines above it, and the fall of the 
water from this refervoir works the machine. There is alfo 
another trough higher up the mountain, v;z. 260 feet above 
the place of delivery K, into which rain-water i<; conveyed 
for the purpofe of working the machine with 2(10 feet fall, 
when a fupply can be obtained therefrom ; but when this 
fupply fails, the machine is worked by the ciftern O with 
143 feet fall. T is an iron-pipe dcfcending from the refer- 
Toir, to convey the water to an air-veflel of copper. A, 
placed at the foot of the mountain near the place of de- 
Bvery. The water from the refervoir O, or from the more 
elevated refervoir, flows through the defcending pipe T, 
whenever the cock H is opened : the pipe T defcends very 
nearly to the bottom of the veffcl A A, as (hewn by the 
dotted lines X, with the intention that the air included in the 
ve(rel (hall be comprclTed when the water enters, and forced 
through the tube L M into a lower veiTel, B, which is fimi- 
lar to A, but only of half the capacity ; it is placed at the 
bottom of the lower mine, which is to be drained at 104 
feet below the dehvery K, and ve(rel A ; this lowTr ve{rel 
receives the waters colleAed in this mine from the trough D, 
through the pipe Q and cock C, and by the force of the 
compreifed air introduced into B by the pipe M from the 
upper ve(rel ; the water contained in B is expelled through 
the pipe S, which defcends to the bottom of the ve(rel B, 
and is difchargcd at Y. 

The wooden trough D is the termination of a trough 
or channel from another engine, which raifcs the water from 
a yet greater depth ; K is a pipe with a cock for difcharg- 
ing the water out of the velTcl A, when the operation is 
over, in order to fill it again with air ready to repeat it, for 
which purpofe the fmall pipe I is likewil'e opened to admit 
air ; the cock L tranfmits and difchargcs air from the upper 
ve{rcl A into the lower velTel, through the pipe M. The 
little pipe E, and its turncock, muft be opened to let out 
the air from the velTcl B, and it muft remain open whilll B 
is filling, by the water from the trough D, through the 
pipe C Q, and it is at the orifice of the little pipe E that 
(now and ice are generated. A valve is placed at tlie lower 
ends of the pipe F S, to prevent the water from efcaping 
out of tlie pipe F S, after it has been raiftd, and whilll the 
ve(rel B is Idling wuh frc(h water. 

The operation is performed thus : two men are placed at the 
▼e(rels A and B to open and (hut the cocks ; fuppofe all the 
cocks (hut, and the refervoir O, at 143 feet high, is always 
full ; the pipe T H is alfo full as far as the cock H ; the refcr- 
Toir D is kept conftatitly full of water from the mine, wliich 
istobe drained by raifing the water from D to F, I04feet ; for 
this purpofe, it mull firft be admitted into the vtlfel B : the 
cock C is therefore opened, and the water flows into B, the 
air being at the fame time fuifcrcd to cfcape from that velTel 
by opening the cock E. The vclTel B is known to be full 
by the emiCTion of water at E, at wliicli inllant both tlie 
cocks C and E are to be clofed. The machine is now pre- 
pared for the operation, which is began by opening the cocks 
H and L ; the defcending water from the refervoir O enters 
the vc(rel A, and compreflTes the included air till its elaltic 
force becomes equal to the prclTurc of the column of water 
D F, and then the air defcends through the pipe M, and 
enters the lower velTel B, where it prelTes on '.lie fiirface of 
fhc water contained in the vc(rel, and forces that water to 
afcend through S to F, which opens into the adit, through 

which the water is difcharged from the mine. This water 
being raifed, the lower vc(lel B is become filled with con- 
denlt'd air in place of the water, and the upper vc(rel A is 
hccome filled with water in place of the air. The cocks 
H and L are th.en (hut, and K and I are opened ; the 
cock K fuffers the water contained in A to flow o(F, and 
I accelerates the difcharge, by admitting the external air 
into the velTel A ; and both thefe cocks are clofed again as 
foon as the evacuation of the upper velTel is completed. 
During this lall operation another man below opens the 
cock E, by which the condenfed air included in the velTel B 
{(Fues witli great force through E ; he then opens C, and the 
water from D again fills the velTel B, as at firll ; this being 
done, he clofcs C and E. 

The apparatus is now charged again ready for aflion, and 
by opening H and L the above operation will be repeated ; 
1'iz. the contents of B will be forced up to F, and thus the 
CT^gine may be kept continually at work as long as the two re- 
fervoirs O at the top, and D at the bottom, arc kept fupplied. 
The dimeiifions of the principal parts, as given by father 
Hell, are as follow, in Hungarian meafure : 

The diameter of the upper vefTcl A 32^ inches ; its 
height 60 inches ; the thickncfs of the copper i^ inches. 
The iron-pipe T is 260 feet ; from H, to the moft elevated 
■ refervoir above O, it is 4^ inches bore ; and the thicknefs of 
the metal is ij inches. 

The lower refervoir O 143 feet above H. 
The pipe F S, 104 feet long, 3^ inches bore. 
Tl.j air-pipe L M is formed narrower towards the bot- 
tom ; at its upper end it is two inches bore, and at its lower 
end I inch ; ihickmfs of the metal I5 inches. 

The Chremnitz foot is to the Paris foot, as 1538 to 1440 ; 
the pound, as 106 to 92. The Paris foot to the Enghfh, as 
32 to 30. 

A cubic foot of water of the mine weighs 72 lbs. 
The upper ve(rel A contains 575 cubic feet, and the 
lower vciFel B 27|. 

Twenty-five cfibic feet are raifed at every operation, and 
fomelimes 31^ feet, as the water defcends from the upper 
or lower rclervoirs at O, the duration of the operation bemg 
di(rerent ; for when the upper ciftern O is nfed at 260 feet 
of elevation, 20 or 21 draughts are made in an hour; but 
when the lower ciftern is ufed at 143 feet elevation, only 17 
or 18 draughts per hour. 

Each of the(e ve(rels is caft in three pieces, which are 
joined by flanchcs and fcrews, with a ring of lead and an- 
other of leather placed between each to fectire the joint, and 
prevent the tranfmilhon of any fluid. M. Jars obfervcs that 
the pipes would have been better if connected by flanches, 
in the manner fticwn by the figure ; but the real praAice is 
to drive tlie ends of the pipes into hollow cylinders of dry 
wood, bound with iron hoops ; thefe anfwcr tolerably well, 
and are of confidcrable durability. 

The moveable plugs of tlie cocks, C, E, K, are fcrcwed 
in t'leir places by caps or covers faftencd down with fcrews. 

The produce of water raifed by this machine is thus efti- 
mated by Dr. Wolfe : 

If the vtfTel A were completely emptied after each opera- 
tion, the cxpence of water, when the fall of 260 feet is ufed, 
would be 1 178. 2j cubic feet in an hour, defcending 206 
feet ; and the elfecl, or the water raifed, would be 563.75 
cubic feet to a height of 104 feet ; or, when the fall of 
143 ftet is ufed, the cxpence ptr hour would be 1006.25 
cubic (Vet, and the e(reft 48 1. 25. But at it is not nece(rary 
that the velTel A (liould be much more than half emptied, 
the ex pence of water will be nearly equal to, or will not 
much exceed the quantity raifed. 



It (hould follow, from experiments on the nature of air, though it anfwers the author's intention, is fo deficient as 
that the column F D is counterpoifed by the comprefled air to the effeft the fame fall of water might produce, as to bear 
in the inverfe ratio of 104 to 32 : hence the volume of air fcarce any proportion ; and there is a defeft in the principle 
contained in the veflel A and the pipe L M, equal to 585 of the machine, viz. that the air will require a confiderable 
cubic feet, muft be reduced to 18 cubic feet, before the fhare of the power to comprefs it, and this air muft be fuf- 
elafticity will be equal to the prefTure of the column C F fered to efcape, before the veflels can be refilled to repeat 
104 feet; but by increafing the compreffion a little more, the aftion ; in confequence, all the power taken to comprefs 
the water in B will be made to Row out through F. the air is loft, and expands itfelf in forcing out a ftrong 

If, at the moment the veflel A is full of water, the blaft of air at the difcharging cock, without producing any 
cock H be fhut, the water will continue to flow through F, ufeful effeft. Notwithftanding this defeft, the cheapnefs 
until the air occupies a fpace of 18 cubic feet in the veflel B, and eafe of conftruftion, and the httle wear and tear, to- 
and in the pipe L M ; the elailicity of the air will then be gether with the facility with which it may be made to work 
in equilibrio with the column F D, and the efflux of the and ftop for very fliort periods of time, are powerful recom- 
water through F will ceafe. In this manner, not above mendations of this machine, in fuch places as afford the re- 
17 cubic fe^ of water are evacuated at each draught, and quifite fall of fuperior water, and do not require a higher 
io| cubic feet are conilantly left in the veifel B. fingle lift than 15 or 20 fathoms. 

But if the cock H is not Ihut the very moment that the A curious phenomenon has been obferved in this machine, 
veflel A is full, the water in A will follow the air through when it is near the end of its operation, that is, when nearly 
L M, and, before it gets to the veflel B, will raife one the whole of the water has been raifed out of the lower 
cubic foot more out of that veflel. After the water from vefl"el B, and the cock E be opened to give vent to the 
A enters into the veflel B, the difcharge at F will not be comprefled air, and before the cock L is fhut, fo that the 
the water of B, but the water of A defcending and afcend- air is followed up by the water, then if a hat or miner's 
ing again by a ufelefs circuit, until H be fhut ; which being bonnet be prefented to the aperture E, the aqueous vapours 
done, the water will continue to flow at F, until the re- difperfed through the comprefled air, and perhaps alfo, 
mainder of 105 cubic feet is expelled from B by the air fays M. Jars, part of thofe of the external air are con- 
contained in it. The moment when the water from A has denfed in the bonnet in the form of very white and compaft 
defcended into the lower veflel B may eafily be known, by ice, very much refembling hail, and not eafily feparated 
the velocity of the elHux at F becoming fuddenly three times from the bonnet. It foon melts, which is not to be woli- 
greater. dered at, as the temperature of the place itfelf is not cold. 

That this is aftually the cafe is proved, becaufe fometimes Meffrs. Du Hamel and Jars remained in Hungary from 
31^ cubic feet are difcharged ; which quantity exceeds the January to July 1758, and obferved the fame phenomenon 
capacity of the veflel B by more than 4 cubic feet. at all feafons ; but as they had no thermometer, they could 

This inconvenience might eafily have been prevented, by not make a number of experiments, which might have been 
giving to the pipe S a diameter of 18 inches ; for then there of value in the inveftigation of the fubjeft. 
would have remained only the juft fpace of 18 cubic feet for It is obferved that the air iffues out with fuch impetuofity, 

the comprefTed air. that the workman could not hold the bonnet at the difl;ance 

The height of the column T to the lowed of the two of a few inches from the aperture, as he does in this experi- 
refervoirs at O is 143 feet, which, taken upon the diameter ment, if he were not fupported behind. The ice is much 
of the veffel A as a bafe, is equal to the weight of 822^ more compaft, if the cock be only in part opened, 
cubic feet, and would comprefs the air into a fourth ; or, When the cock at which the air is difcharged is opened, 
when the water is defcending into the lower veflel B, into a it rufhes out with prodigious violence, and the drops of 
feventh part of its natural fpace, provided it were equally water are changed into hail or lumps of ice. It is a fight 
refilled at F. The veffel A becomes filled at a mean in ufually fhewn to ftrangers, who are defired to hold their 
8 feconds ; and in twice that fpace of time, 1 7 cubic feet hats, to receive the blafts of air : the ice comes out with 
are evacuated through F. fuch violence as frequently to pierce the hat like a piftol 

The power of the column of 260 feet from the mofl ele- bullet. This rapid congelation is a remarkable inftance of 
vated refervoir, aAing wthin the veffel A, is equivalent to the general faft, that air, by fuddenly expanding, generates 
the weight of 1495 cubic feet of water. It can raife a cold ; its capacity for heat being increafed. 
greater quantity, if the veffel B be fo conftrufted as to The formation of the ice and fnow, when the condenfed 
allow no more than a juft. fpace to the comprefled air. If air rufhes out of this machine, has been explained in a dif- 
the veffel A were filled in 4 feconds, then 17 cubic feet of ferent way in almoft every fyftera of philofophy. It ap- 
water would be difcharged through F in twice that time, pears to us to be a neceffary confequence of the condenfed 
and the air would be reduced into an eighth, and, during air, on rufhing out into the open air. 

the defcent of the water of the veffel A into the lower veffel The air of the atmofphere, and the water when taken into 
B, into an eleventh part of its bulk. But this makes no the machine, are nearly of the fame temperature ; and it 
alteration as to the quantity of the effeft ; and when water may be confidered that each cubic foot of water and of air 
ceafes to flow out at F, there will always remain 10^ cubic contains fome certain quantity of heat or caloric ; but they 
feet of water in the veffel B. will readily impart a portion of this heat to any body contain- 

Two men are required to attend it, but it would be very ing a lefs degree than themfelves, or they will abforb or take 
eafy to conneft the levers of the cocks above and below, fo up heat from any body containing a greater proportion of 
as to require only one man to work the whole fet ; and in- heat than themfelves, in confequence of that property of heat, 
deed there would be little difficulty in making the machine by which it will diftribute itfelf equally among all bodies 
work itfelf fafely, without any attendant, except to fet it which are in contaft with each other. By the adion of the 
oS' at firft, or ftop it when requifite. The machinery for machine, the air is comprefled into one-third of the fpace it 
this purpofe has been propofed by Mr. Bofwell. See Nichol- before occupied, and the fhare of heat contained in that air 
fon's Journal, 4to. iv. 117. is likewife concentrated or thrown into a third of the fpace. 

From what has been faid, it is evident that this machine, and in confequence becomes more intenfe. Some part of 
Vol. XXXVIII. I the 


the heat will, therefore, be communicated to the furround- its bulk by the column of 136 feet high ; for a column of 
ing water, until the heat diftributes itfelf again between the 34 feet nearly balances the ordinary elafticity of the air. 
water and the condenfed air, fo that they come to the fame But when there is an iffue given to the air through the air- 
temperature. In this ilate, if the air is fuffered to rufli out pipe, it will drive the comprcfled air along this pipe, and it 
of the veffel, it will fuddenly expand and recover its former will expel water from the lower cyhnder. 
volume, and it muft alfo recover its former (hare of caloric, When all the air is expelled from the upper cylinder, 
which it can only do by abllrafting heat from the furround- there will be 34 cubic feet of water expelled from the lower 
ing air, or from any fubftance witli which it comes in con- cyhnder. Now if the afcending pipe had been carried up 
taft : hence the coldnefs of the blaft of air. In rcfpeft to more than 1 36 feet above the lower level, inftead of 96 feet, 
the formation of fnow and ice, it mull be confidered that the then the water would have rifen 136 feet high in that pipe, 
air of damp places always contains a confiderable portion of by the intervention of the elaftic air, before it was in equilibrio 
water in a ftate of vapour, and the air in thio machine will with the water in the defcending pipe ; but no more water 
have taken up more than the ordinary (hare, in confequence would have been expelled from the lower cyhnder than what 
of being in contaft with the water. When the air expands would (ill this pipe. 

itfelf, the heat being fuddenly abllrafted from this watery But the afcending pipe being only 96 feet high, the water 

vapour, it becomes fluid, and accumulates in drops hke willbe thrown out at the top of it with a confiderable velocity, 

rain ; which drops, by a farther abftraftion of heat, become Were it not for the great obftruAions which the water and 

folid like fnow or hail. air muft meet with in their pa(Tage along the pipes, it would 

An inftrument which is in common ufe to produce fire, ilTue from the mouth of the afcending pipe with a velocity 

by the fudden compreffion of air, (hews the reverfe of this of more than 50 feet per fecond. It ilTues, however, much 

aftion : it is a fyringe fitted with a pi (Ion, which is air-tight ; more (lowly. 

at the bottom of the barrel a fmall piece of tinder is placed. When the upper cylinder is become filled with water, the 

Now, if the pifton is very violently and fuddt-nly forced fupply is (lopped ; but the lower cylinder (lill contains 34 

down to the bottom of the barrel, and the pillon is then cubic feet of comprelTed air of fufficient elafticity to balance 

withdrawn, the tinder will be found on fire. The heat con- the water in a difcharging-pipe 136 feet high, whereas the 

tained in the air which fills the barrel is fo concentrated at afcending-pipe is only 96 feet. Therefore the water will 

the fame time witli the air, as to produce adlual fire. If continue to flow at the mouth of the afcending-pipe till the 

the pillon is forced (lowly down, the air will be condenfed comprelFed air is fo far expanded as to balance only 96 feet 

to an equal degree, but no fire will be produced, becaufe of water, that is, until it occupies one-fourth of its ordinary 

the heat has time to efcape through the metal of the barrel, bulk, or one-fourth of the capacity of the upper cylinder, 

before it ai-rives at any confiderable degree of concentration, vix. 42^ cubic feet. Therefore 425 cubic feet of water 

We confider that in all cafes when air (and perhaps other will be expelled, and then the efllux will ceafe, leaving the 

elaftic fluids) is comprelTed imto a fmaller fpace, part of the lower cylinder about one-half full of water, 

heat it before contained will be given out to the furrounding When the difcharging-cock of the upper vc(rel is opened 

matter; or if it is fulfered to expand to fill a larger fpace, the water iffues with great violence, being pre(red by the 

it will abforb or take up heat from the furrounding matter. condenfed air returning from the lower cyhnder. It vhcrc- 

A largir Machine at Chremnitz Tliis does not differ fore iffues with the fum of its own weight, and of this com- 

from the original machine, fo as to require a minute defcrip- preffion. Thefe gradually decreafe together, by the efllux 

tion ; but as this machine is not employed in England, and of the water and the expanfion of the air ; and this e(flux 

we think it might be ufcful in many cafes in mining diftrifts, flops before all the water in the upper velTcl has flowed out, 

we (hall give the proportions and calculations of a larger becaufe there are only 42^ feet of the lower cylinder occu- 

machine, as a model for engineers. pied by air. This quantity of water nearly will therefore 

P remain in the upper cylinder. The workman knows this, 

Height of the fource above the place of delivery! ' " becaufe the difcharged water from the upper vcflel is 

or fall of water, which is to work the machine : [■ 136 --eceived firft of all into a vefl^el contaimng three-fourths of 

defcending pipe 4 inches bore - - - 3 f^ "P^^^'^y "[. "-^^ "PP" '^yl'"'^^'-' «;'"<^'' ^''"'^ ^ ^ «""- 

Depth from which the water is to be raifed out of! f"-"^ ^ «1"^" t»"^ '^ fi'l'^.'J' "f attendant opens the cock 

tie pit to the place of delivery : afcending pipe J- 96 ^' '"^^ admits the water into the lower vefl-el by a long rod 

.'^, ."^ _ _ ".\ which goes down the (haft : this allows the water of tlie 

* ,. , . T- mine to fill the lower cyhnder, and the air returns into the 

Cubic reel. v j i i_ ^i • • j ■. .1 

_, ,. J r .. J- » -V upper cvhnderthroueh the air-pipe, and permits the rcmaiii- 

UoD€r vefTel a copper cyhnder t feet diameter, j ■ ^ ^' ^ r r ■.. / \ fu .. i . c j 

ufpct '•^"" » >: yi" } .3 'I ,ngr water to run out of it ; and when the attendant finds 

and 84 feet hieh : metal 2 inches thick; the I b ... ' .1 • • i i . . •. 

,"°5 ."fi ' ,. . , r ,i,„ > 17° no more water will come out, every thing is brought to Its 

defcendmg pipe goes to within 4 inches of the f ^^^^ condition. ' / s b 

bottom: contents ' " / .. ' 'J The above account of the procedure in working this 

The lower veffel a brafs cyhnder 4 feet diameter, 1 . .1 . .1 m .a „ .1 r.i r j- 

, ,,' ,. , ', • T .u- I .u / entrine, (liews tliat the efflux at the mouth of the afcendinc- 

and 64 feet hitfh ; metal 2 inches thick; the { „ -^ u n .1 j r» .u- . -.^ 

' ? . o ' , , , > Vi ninf hiTomps vprv 1 ow near the end. (Jn this account, it ii gee. withm 3 inches of the bot- ( |;^|;_^j convenient not to wait for the complete difcharge, but 

torn: capacity - .'",.' .lil ,..,^1 to cut off the fupply when about 30 cubic feet of water 

Air-pipe which communicates between the two I , , rr i j j~ 1 ■ j .u- 

%-K • 1 , J /- r . ■ 1 .u f have been dircfiarired, and more work is done in this way. 

velTels. 2 inches bore, and go teet in length -I a .1 r . j 1 1 j r .1 r 

' > y b J ^ gentleman of great accuracy and knowledge of tliefe 

To underftand the aAion of this machine clearly : — Sup- fubjt6ls, took the trouble of noticing particularly the per- 

pofe that the lower cyhnder is charged with water, and the formance of the machine. He obferved that each ftroke, as 

upper cylinder with air ready for aftion ; when the water it may be called, took up about three minutes and one- 

from the fource is admitted into the upper cylinder, if no eighth, and that 32 cubic feet of water were difcharged, and 

ifTuc was given to the contained air, the water would enter 66 cubic feet were expended. 

hito the veffel, until the air wa» comprcffed into one-fifth of The cxpencc therefore in 66 cubic feet of water falling 



136 feet, and the performance is 32 cubic feet raifed 96 feet, have therefore preferred to defcribe a machkie of the fame 

and they are in the proportion of 66 x l36to32 x ()6,-viz. kind invented by Mr. Goodwin; he calls it a machine 

8976 to 3072, that is the power employed is to the effeft that will raife a body of water to any height not exceeding; 

produced, as 2.9 to i. The quantity raifed, -viz. 32 cubic the height of that column which will counterbalance the 

feet, divided by the time 3^ minutes, gives very nearly 10 preffure of the atmofphere, (fay 30 feet) and afts by the 

cubic feet per minute, and multipUed by the height raifed defcent of part of the fame body of water through a foipe- 

96 feet = 960 cubic feet raifed i foot high. Divide this what greater height, aided by the preffure of the atmo- 

by 528 cubic feet, which is the horfe-power, and it gives 1.8. fphere. 

The machine is not therefore equal in effedlive power to a Let A,^. 10, Plate Waier-'works, be a fpherical veffel of 
fleam-engine of two-horfe power, but the power employed eopper or other metal, about 18 inches diameter ; B, anothpr 
is juft equal to five-horfe power. fphere, about two feet fix inches in diameter ; C, a refer- 
When we confider the great obftruftion which water voir kept conftantly fupplied with water, part of which is 
meets with in its paffage through long pipes, we find we to be raifed up to E, by the power of another part defcend- 
may gain fome advantage by increafing the bore of the de- ing to a confiderable depth beneath the refervoir C. D is 
fcending-pipe of fupply. The quantity of water which a glai's cap, about fix inches long, fixed on the top of the 
defcends through this is 66 cubic feet in 3-! minutes, or very upper veffel A, for the purpofe of feeing when the water 
nearly 30 cubic feet per minute ; the area of the four-inch begins to fill and has filled it ; E is the upper refervoir into 
bore is 12.5 fquare inches, and therefore 1 1.5 fuch areas which the water of the refervoir C is to be elevated, and the 
would make a fquare foot. Multiply 30 cubic feet by n.j, contents of the upper veffel A is to be emptied; i is a 
and we have 345 feet, which is the velocity with which the pipe about half an inch in diameter, joined into the top of 
water muft defcend in the pipe. This is much too great, the lower veffel B, and rifing upwards to within about an 
and it would be an improvement if the pipe was increafed to inch of the top of the glafs cap D of the upper veffel • 2 is 
fix inches bore, and the velocity would then be only 151 a pipe of the fame diameter, and a few feet longer than i, i 
iceXper minute. The performance of the machine would joined to the bottom of the lower veffel B, and defcendinjr 
then be greatly increafed, we think as much as one-third ; downwards in a perpendicular or inclined direftion to a 
it is true that it would expend more water, but not in the rather greater diflance beneath C than the upper veffel A is 
fame proportion ; for part of the deficiency of this ma- elevated above C ; 3 is a pipe one inch and a half in diame- 
chine arifes from the needlefs velocity of the water in the ter, joined to the bottom of the upper veffel A, and paffmg 
pipe, as well as from the violent efflux of the water by the upwards through the bottom to within two inches of the 
condenfed air, as we have before mentioned. top of the glafs cap D ; 4, 4, is a pipe of about half an inch 
The difcharging-pipe ought to be 1 10 feet high inttead of diameter, joined to the top of tlie veffel B, it paffes through 
96, and would not give fenfibly lefs water. It muft be con- tiio bottom of the refervoir C, and rifes above the furface of 
fidered if the original expence of this fimple machine would the water therein ; J is a pipe of the fame diameter, fixed to 
not be lefs than a water-mill which would raife 10 cubic feet the top of the veffel B, and terminating in and fixed to the 
of water, 96 feet high, in a minute ; the repairs of it would bottom of the refervoir C ; a is a pipe or fpout of the fame 
be fmall when compared with a mill. And, laftly, let it be diameter, fixed into the bottom of the upper veffel A, to 
noticed, that fuch a machine can be ufed where no mill convey the water into the refervoir E ; 7 is a trumpet 
whatever can be put in motion. mouth-pipe fixed to the bottom of the pipe 3, and extend- 
A fmall ftream of water, which would not move any kind ing downwards beneath the water to within about an inch 
of wheel, will raife one-third of its own quantity to the of the bottom of the refervoir C ; a, b, c, and d, are cocks 
fame height, working as faft as it is fupplied. fixed to the pipes. The veffels, pipes, cocks, and joints. 

From its fimplicity, we think the Hungarian Machine muft all be air-tight. 
(whichfee)eminentlydefervestheattentionof mathematicians In order to raife water from the lower refervoir C into 

and engineers, to bring it to its utmoft perfeftion, and into the upper refervoir E, all the cocks being ftiut proceed 

general ufe. There are many fituations where this kind of ma- thus: open the cocks b and c, in order to fill the lower 

chine may be very ufeful. Thus where the tide rifes 1 7 feet, it veffel B, and when B is filled, ftiut the cocks b and c, and open 

may be ufed for compreffmg air into feven-eighths of its the cock d. The water will then begin to run from the 

bulk, and a pipe leading from a very large veffel inverted in fphere B by its gravity, and by means of its communication 

the tide- water may be ufed for raifing water from another with the upper fphere A, through the pipe i, will draw off 

veffel of one-eighth of its capacity, 15 feet high ; or if this the air therefrom to fupply the fpace left in the lower veffel 

veffel has only one-tenth of the capacity of the larger one B, by the running out of the water the air in A is thus rare- 

fet in the tide-way, two pipes may be led from it, one into fied. The atmofpheric air at the fame time preffmg on the 

the fmall veffel, and the other into an equal veffel, 1 6 feet water in the refervoir C, will caufe it to rife through the 

higher, which receives the water from the firft. Thus one- trumpet-mouth 7 of the pipe 3, and by faUing over the top 

fixteenth of the water may be raifed 34 feet, and a fmaller of the pipe 3 at D, it will fill the upper fphere A. When 

quantity to a ftill greater height, and this with a kind of A is full, which may be feen through the glafs cap D, ftiut 

power that can hardly be applied any other way. the cock d, and open the three cocks a, b, and c, the cock 

Sipho Interruptus to raife Water by Suclton — This machine and pipe b will allow the atmofpheric air to return into the 

is the reverfe of the Chremnitz machine in its aftion, for veffel, and fill both with air, by which means the water eoi>- 

the power of a defcending column of water, running out of tained in the veffel A will run into the elevated refervoir E, 

a clofe veffel, canfes a vacuum therein ; and another column and B will be repleniftied for another operation. Then ftiut 

of water is fucked up into the veffel, or rather forced up the cocks a, b, and c, and open the cock d, and it will rc- 

by the preffure of the atmofphere to fill the vacuous fpace. peat the operation of raifing the water into A. 
This machine is fully defcribed by Leopold, in his Theatrum If it be required to raife any body of water from refer- 

Machinarum Hydraulicarum, vol. i. It is provided with voir C into refervoir E, by means of the defcent of a body 

apparatus to open and ftiut the cocks. It would be diffi- of fome other water from the veffel B, a communication 

tult to explain this machine without feveral figures, and we muft be made into B, independently of the pipe j, an'l 

I 2 cock 


cock c \ viz. through a pipe-cock leading from another 
refervoir, as is repreftnied by tlie dotted lines communi- 
cating with B near the pipe and cock 5 ; the aftion is the 
fame as before ; but the cock with the dotted hnes is to be 
ufed in lieu of pipe 5, and cock c. By this means, if the 
water which is employed to work the machine is foul or 
tainted, it will have no communication with the water which 
it raifes. This machine has the fame defeft as the Chrem- 
nitz macliine ; viz.. that the power which is expanded in 
rarefying tlie air is greater than the quantity of water raifed, 
and the difference is loft when the cock in the lower veffel 
is opened, and the air ruflies in. 

^ diffcrtnt Form of the Siphon Machine. — Mr. Goodwin's 
engine is formed upon a very elegant principle, and operates 
by the afliftance of only a fmall quantity of water. It may 
be made in various forms, either to raife the fluid above the 
defcending column, or from below it to a level with the 
bottom, and the height may be doubled or trebled by pro- 
portionally increafing the defcending mafs, and raifing fe- 
deral columns of water from different elevations at the 
fame time, by combining two or more of tlie fimple 
machines together, as is ihewn in_^^. 8. Plate Water- 

C, as in the former figure, reprefents the refervoir or 
fource of water which is to work the machine ; B repre- 
fents the loweft of the two veflels which contain the rifing 
and defcending bodies of water ; and the fmall fquare near 
fig. 8. reprefents the upper vefiel A, Jig. 10. Thefe veflels 
are fpherical in the original drawing, but to leflen the lofs of 
Q>ace in defcent, they are here made flat and cyUndrical ; 
E is the higher ciftern of the original figure, into which the 
water is to be raifed ; 2, 3, and 4, are the pipes arranged in 
the fame manner as the former machine ; F, a veflel the fame 
as A, with tubes 3 and 6 : it communicates with the 
veffel B by a pipe, and is intended to raife water out of the 
ciftern E into a higher and additional ciftern G. 

The veflels E, F, and G, form a fecond machine, which 
has the fame parts and properties as the former, except that 
the lower veftel B is common to botli, and ferves as the 
lower veffijl to exhauft and drive up the water both to A 
and to F ; 2 is an enlarged tube like the original drawing, 
tlirough which the water defcends to produce the aAion ; 
5 is a hole in the top of B, inltead of a tube. This hole, 
and the tubes 2, 4, and 6, muft be provided with valves inftead 
of cocks, which muft be kept clofe by weights or fprings, 
(while the water is rifing) except the valve to tube 2, 
which muft be open. The tubes 3, J, may alfo have valves 
to fupport the raifed columns. 

Operation. — Fill the cifterns C and E with water, and let 
the tower ciftern be conftaiitly fupplied ; open tlie v.ilves of 
the tubes 4, 5, 6, 6, and clofc the valve of the defcending- 
tube 2, the veflel B then becomes filled through the hole 5. 
Now cloft the valves of the tubes 4, 5, and 6, and open the 
valve of the tube 2, the water will then begin to defcend 
out of B, and will exhauft the air from A and F, juft as in 
the firft-meiitioncd machine ; the prcffure of the almo- 
fphtre on the furface of the water C, will raife one body of 
water out of C into A, and out of E into F ; when B is 
nearly empty, or when A and F are full, open the tubes 
4, 5, 6, 6, a™J clofe 2, then B will be filled a fecond time, and 
the veflels A and F will empty themfelves into their rcfpcc- 
tive cifterns E and G : thus the reciprocations continue 
without interruption. 

Another body of water may be raifed out of G into a 
higher ciftern by additional apparatus, and by proportion- 
ally increafing tlic dimenfions of the veflel B and the tube 2. 
The dotted hnes reprefcnt the apparatus for raifing water 

below the bottom of the tube 2, to be ufed inftead of thofe 
above the ciftern C. 

This arrangement of the engine is of great utility in 
many cafes ; and iu fituations where this machine can be 
erefted, it may be of confiderable ufe for raifing water out 
of mines for draining pieces of land, or elevating t!ie water 
employed in domeftic purpofes. 

Comparifon of deferent Prejfure-Engines. — In Mr. Nichol- 
fon's Journal, 8vo. vol. i. Mr. Bofwell has given a plan for 
conftruding Mr. Goodwin's engine on a large fcale, to 
operate without attendance of any perfon, to open and (hut 
the cocks, and another method of caufing the Chremnitz 
machine to raife water above the level of the prime refer- 
voir ; and he makes the following comparative view of the 
advantages of both kinds of engines and their powers. 

It will be found that the powers and capabihties of thefe 
machines are nearly fimilar. ift, In both the greater tlie 
height of the original fall of water from the fource to the 
difcharge, and the greater the quantity of water which it can 
fupply in a given time, the greater quantity can be raifed by 
either of thefe engines in a given time. 2dly, Both engines 
can be conftrufted fo as to raife water above the original 
level, and from below, to the furface, or from a pit. 3dly, 
By a fucceffive number of refenroirs, both engines can be 
brought to raife water to any height, but as they will raife 
a fmaller quantity as the height is increafed, the quantity 
wanted in a given time, and the expence of conftruftion, will 
limit the extent of their elevation. 4thly, In both engines 
the diftance of one refervoir from another muft always be lefs 
than that of the original fall : the circumftances in which 
thefe engines differ arife from the difference in their manner 
of aftion. fthly. The Chremnitz engine operates by cauf- 
ing a fall of water to comprefs the air, wliich reafting on 
other water, forces it to rife in a pipe to a certain height. 
The fyphon engine aAs by caufing a fall of water to rarefy 
a certain quantity of air, in whofe fpace the preffure of the 
atmofphere forces a quantity of water when permitted. 
6thly, Hence in the Chremnitz engine the preffure afting 
from within outwards tends to burll the veflels ufed in the 
ftrufture, and to open and extend any fiffures which may 
chance to be in them, ythly, In the fyphon engine, the 
preffure afting from without inwards, clofes all the parts of 
which it is compofed more together. 8thly, The Chremnitz 
engine will always raife water of a height nearly to that 
of the original fall from one refervoir to another, fuppofing 
the original fall of any height whatfoever as 100 feet. The 
fyphon engine will not railc water by one refervoir fo high 
as thirty feet in any cafe whatfoever, as there cannot be a 
complete vacuum formed by it iii the air-chamber, but only 
an approximation to one. 

From this comparifon, it will follow that wherever the 
original fall of water is lefs than thirty-two feet, the fyphon 
engine will be much preferable to the Chremnitz, as from 
the feventh article of the comparifon it may be made of 
the cheapcft materials, fuch as llrong wooden calks and 
wooden pipes, whereas tlie Chremnitz engine from tlie fixth 
article muft be made of the ftrongeft, and of courfe the molt 
collly materials, as metal, and that of confiderable thicknefs ; 
but wherever tiie original fall exceeds the height of thirty 
feet confiderably, and it is required to raife the water to 
nearly the fame height, then the Chremnitz engine appears 
to be preferable, as, in all probability, the fewer number of 
parts which it will require in this cafe will more than com- 
penfate for its coft in materials. 

When it is required to raife water to a height much greater 
than that of the original fall above the firll level, or from a 
greater depth, cither from the original fall being fliort, or 



the required height being great, it is better to employ an 
engine in which the preiTure of the water is made to aft by 
a pifton in an apparatus fimilar to that of a fteam-engine. 
( See our article Pressure Engine. ) When neither the fy- 
phon engine nor the Chremnitz can be ufed without a 
number of refervoirs, then the pifton prefTure-engine ought 
to be preferred, but this will much depend on the number 
of refervoirs ; for perhaps one or two in addition to the 
Chremnitz might coft lefs than boring the cyhnder of the 
pifton-engine perfeft, and conftrufting its additional ma- 
chinery. For merely railing water the powers of each are 
nearly equal, depending entirely on the height of the original 
fall of water. 

It would be a great advantage of the pifton-preffure engine 
if a fall of water could be applied to it without any walte, to 
work mills or machinery for any purpofe; this would be of 
very great confequence when the fall of water is of con- 
fiderable height, and the ftream or fupply fmall. We have 
mentioned the advantage in this engine to have its aftion made 
elaftic, by the addition of an airohamber, on the fame prin- 
ciple as that ufed in engines for extinguifhing conflagrations. 
Mr. Bofwell fuggefts that this might be effefted by making 
the pifton hollow, and of a larger ilze, to contain air for this 
purpoie, as the air's elafticity would then aft both on the 
upper and lower prelTure of the water. 

Machine for raijing Water by the lateral C ommunication, from 
the Motion of a Stream of Water running through a conical Tube. 
— This machine operates by fuftion, or more properly by the 
preffure of the atmofphere, and is in fome reipefts fimilar to 
the fyphon machine. (See fig. 9. Plate Water-works.) 
A A reprefents a refervoir of water kept conftantly full, at 
the fame time that the conical fpout, B, is running full under 
a confiderable prefTure ; D, a fpherical copper veflei, with a 
tube, C, joined into its bottom, and rifing up within to fome 
height above the centre of the fphere ; E, another tube joined 
to the bottom of the fphere D, and terminating near its top ; 
the lower part of this tube is bent, and the extremity of 
it is introduced into the fmaller apertures of the conical 
tube B ; F, a fpout or tube to empty the veffel D, when it 
is filled with water which has been raifed up out of the re- 
fervoir A ; G, a fmall tube paffing through the fpout F, and 
rifing to near the top of the fphere, D, for the admilfion of 
air to quicken the defcent of water out of that veiTel. Both 
thefe tubes are clofed at their lower ends by a leather valve 
at the end of the lever L, which lever is fixed upon the 
turning plug of a cock in the tube E, and has a weight upon 
one end, in order that the other end may bear the valve up 
againft the openings of the tubes F, G, vsrith a confiderable 
force, and alfo to fupport the weight of the fmall bucket I, 
which is fufpended from the lever by a wire (at lealt when 
the bucket is empty) ; H is a fmall ciftern to be filled with 
water from the refervoir A, in the fame time that the 
water is raifed up into D ; this muft be done by regulating 
the cock, k, upon the pipe which iupplies the ciftern with 
water. The ciftern H is provided with a fyphon, which will 
begin running as foon as the veffel is full of water, and will 
foon empty it. The fmall bucket I, which is fufpended 
from the lever L, is alfo furniftied with a fyphon-tube, which 
will begin to run and empty the bucket whenever it is quite 
full, but not before. 

The operation of the engine will be as follows : — The re- 
fervoir A being kept conftantly full of water, and the coni- 
cal tube B completely filled at its wider end by the water 
which runs out of A, the force of the lateral motion of the 
fluid will be increafed by the conical form of the tube B, 
and will aft upon the end of the tube E to draw air out of 
the fame, fo as to rarefy the air in the veffel D ; and the pref- 

fure of the atmofphere upon the furface of the water in the 
refervoir A, will caufe part of that water to rife up the 
pipe C, to run over its top and fill the fphere D ; it will then 
defcend through E, and join the ftream of water which flows 
out at B. When the veffel D is full of water, if the valve at 
the fpout F is opened, the water will run out. 

In order to open the valve the cock k is regulated, that 
the ciftern H will be filled foon after D is full, and the 
fyphon of this ciftern beginning to empty the water it fills 
the bucket I, which then overbalances the weight upon the 
lever L, and opens the fpout F, and air-pipe G, and at the 
fame time clofes the cock in E ; the column of water in the 
defcending pipe C immediately defcends into the refervoir, 
and if the fmall tube G be full of water it will be emptied 
by the defcent of that column, and will admit air into D fo 
as to allow the water to flow out at F into the elevated re- 
fervoir. The fyphon in the ciftern H is regulated fo that 
the ciftern and the veffel D will be empty of water about 
the fame time, and the bucket I by its fyphon will become 
empty foon after : the weight upon the lever L will then 
clofe the fpout F, and open the paffage through E, when 
all the parts will ftand as at firft ready for a repetition of 
the operation of the lateral aftion of the ftream, by which 
the water is raifed up into D as before. 

If the water ftiould defcend through E before F and G 
are opened, it will render the cock in E more tight. To 
quicken the reciprocation of the engine, and increafe the 
quantity of raifed water, a valve may be m.ide to fupport 
the column of water in the fuftion-pipe ; this valve may be 
placed in a cheft at the bottom of the pipe. 

The defcending branch of the fyphon in the higher veffel 
H ftiould be made of confiderable length, to prevent a con- 
ilant dripping, and make the reciprocation end at once ; 
the fyphon of the bucket I (hould fall as large in bore as 
the other, in order that the weight on L may preponderate 
quickly, and clofe the valve immediately. 

The inventor entertains no doubt refpefting the operation 
of a machine of this kind, and that a column of water may 
be raifed to any height not exceeding thirty feet by pro- 
portionally increafing the preffure of water in the refervoir, 
and the dimenfions of the conical tube. 

In many fituations, however, the requifite quantity of water 
for this purpofe cannot be had, and others may not admit of 
fufficient defcent. 

Where the ftream has a confiderable defcent, the water 
may be raifed by a number of lifts inftead of one, by com- 
bining as many machines. Suppofe three refervoirs each 
with its conical tube or fpout through which the water runs 
from one to the other ; alfo three exhaufting veffels each 
with its elevated ciftern into which the raifed water is to be 
dehvered ; and the fuftion-pipe of each veffel draws its water 
from the elevated ciftern of the veflei below it. From each 
exhaufting veffel a pipe is conveyed to the conical fpout of 
one of the three refervoirs, and the lateral motion of the 
ftream paffing through the fpouts of the three refervoirs will 
aft upon all three engines at once. 

In like manner, when there is plenty of water, but not 
convenience for a deep refervoir, feveral conical fpouts may 
be fixed to different parts of the refervoir, and all upon the 
fame level. Each machine muft be provided with z. lever 
and weight to work its own valves, but they may be all 
opened at the fame time by the defcent of one veffel con- 
nefted with all the levers, or each may have its refpeftive 
bucket and lyphons. 

This kind of machinery, by altering the pofition of the 
rarefying tubes, may be made to raife water from a depth 
below the ftream equally as well as to a height above it ; and 


in fituations where there is plenty of water and convenience 
for a refervoir a lower body of water may be conveyed into 
a ftream above by the help of a fingle tube, one end of 
which is placed in the water to be raifed, and the other muft 
be introduced into the fmaller aperture of the conical tube 
adapted to the refervoir ; a contlant ftream will then rife, 
fo long as water below can fupply the tube. 

Mr. Whitehurji's Machine for raifing Water by its Mo- 
mentum Fig. 7, Plate IVater-woris, is a reprefentation of 

the firft machine on this principle, which was executed in 
the year 1772, by the ingenious Mr. John Whitehurft, at 
Oulton in Chefliire, at the feat of Mr. Egerton, for the fer- 
vice of a brew-houfe and other offices, and which purpole it 
was found to anfwer efFeftually. This firft form of the 
momentum machine would be a ufeful application in many 
fimilar Ctuations. The circumftances attending this water- 
work are as follow : A reprefents the fpring, or original re- 
fervoir, which fupplies the water, the upper furface coincides 
with the horizontal hne B C, and the bottom of the refer- 
voir K, into which the water is to be raifed ; D is the main- 
pipe, one inch and a half in diameter, and nearly two hundred 
yards in length ; E, a branch-pipe, of the fame dimenfions, 
for the fervice of the kitchen-offices. It is to be obferved, 
that the kitchen-offices are fituated at leaft eighteen or 
twenty feet below the furface of the refervoir A ; and that 
the cock F is about fixteen feet below it. G reprefents a 
valve-box, and^the valve within it ; H is an air-veflel, and 
O, O, are the two ends of the main-pipe, inferted into the 
air-veffel H, and bending downwards, fo that in effeft the 
pipes communicate with the loweft part of the veflel, and the 
air cannot efcape when the water is forced into it, but it 
muft be comprefled by the column of water ; W is the fur- 
face of the water in the air-veflel. It is well known from 
theory that, when water is difcharged from an aperture, under 
a preuure of fixteen feet perpendicular height, it will move 
at the rate of thirty -two feet in a fecond ; the velocity of 
the water from the cock F will be nearly as much, making 
fotne allowance for frlAion and refillance ; and although 
the aperture of the cock F is not equal to the diameter of 
the pipe D, yet the velocity of the water contained in the 
pipe will be very confiderable ; confequently when the cock 
is opened a column of water two hundred yards in length is 
put into motion, and if it is fuddenly ftopped by the Ihut- 
ting-cock F, its momentous force will open the valve g, 
and condenfe the air in veflel H ; this aftion will be repeated 
as often as water is drawn from F. It is needlefs to fay in 
what degree the air is thus condenfed in the inftance before 
us ; but it will be fufficient to obferve, tliat it was fo much 
condenfed as to force the water up into the refervoir K, and 
even to burft the veflel H, in a few months after it was firlt 
conftrufted, although it was apparently very firm, being made 
of fheet-lead, about nine or ten pounds weight to a fquare 
foot. Whence it is reafonable to infer that the momentous 
force is much fuperior to the fimple prefigure of the column 
in the refervoir K, above the level line C B, and tlierefore 
equal to a greater refiftance (if required 1 than a prefigure of 
four or five feet perpendicular height. It may be ncccfi^ary 
farther to obferve, that the confiimption of the water in 
the kitchen-offices is very confiderable, becaufe water is fre- 
quently drawing from morning till night all the days of 
the year. 

From this account which is publiftied in the Philofophical 
Tranfaftions for 1775, '^ '* clear that Mr. Whitehurft was 
lully aware of the power of the momentum of running 
water, and though he applied it only to raife water to a 
fmall height, he knew it might be carried to a grciter 

Montgoljur's Hydraulk Ram. — We have given the ac- 
count of Mr. Wlutehurft's machine, becaufe it (hews the 
firft origin of a moft valuable invention, which was after- 
wards praftifed in France by M. Montgolfier, the inventor 
of the firft balloon with heated air. Mr. Boulton took a 
patent in England for Montgolfier's machine in 1797; he 
afterwards ;alled his machine belier hydrauliqae, that is, hy- 
draulic ram, becaufe of the ftiock which the water makes 
when its motion is fuddenly ftopped. In his publication in 
the Journal des Mines, vol. xiii. he fays, " This invention 
is not originally from England, but belongs entirely to 
France ; I declare that I am the fole inventor, and that the 
idea was not furniihed to me by any pcrfon. It is true 
that one of my friends, with my confent, fent to Meflrs. 
Watt and Boulton copies of feveral drawings of this ma- 
chine with a detailed memoir on its applications. Thefe 
are faithfully copied in the patent taken out by Mr. Boul- 
ton in England, dated December 13, 1797, as that gentle- 
man has avowed." We do not wi(h to detraft from the 
merit of M. Montgolfier, as we believe that Whitehurft's 
machine was unknown to him, but we muft ft ate the 
hydraulic ram an Englifh invention. To have an idea of 
this invention, it is proper to ftate its phyfical principle of 
aftion, which is as follows. 

When water is running with a rapid current through a 
pipe or clofe channel, if the end at which the water iflues 
be fuddenly ftopped, the water (by its acquired motion, 
momentum, or impetus,) will aft upon the fides or circum- 
ference of the pipe, and endeavour to efcape with a force 
proportioned to its quantity and velocity. If the materials 
of the pipe are ftrong enough to refill that impetus, the 
water may be made to ifl"ue with violence and velocity, at 
any aperture which is opened in or near the clofe end of the 
pipe ; therefore if an afcending pipe be joined to that 
aperture, a portion of water will afccnd in it. The machine 
being provided with proper valves, to prevent the return 
of the water fo elevated, the operation may be repeated in 
a conftant fucceffion, and will form a kind of perpetual 

The fame effeft will be produced by a different arrange- 
ment of this apparatus, "vit. a pipe open at both ends, with 
a valve and afcending-pipe, fuch has as been defcribed. Let 
this be fo attached to fome kind of machinery, that it can be 
fwiftly moved along, in the direftion of its length, through 
ftanding water ; then, upon clofing the hinder part of the 
pipe fuddenly, a portion of water will be forced up in the 
afcending-pipe, in the fame manner as in the former cafe, 
and for the fame reafon, becaufe the water will be relatively 
in motion with refpeft to the pipe. 

The fame principle may be readily extended to raife 
water by fuftion from a lower level than that on whicli the 
niachine is placed, and this by either of the means above- 
mentioned. Suppofe a fuftion-pipe, which communicates 
with water at a lower level, be joined to the main-pipe 
through which the water flows, and that the junftion is 
near that end of the pipe where the water enters into it. 
Suppofe alfo that the water has acquired a rapid motion 
through the pipe, either by the current of water running 
through the pipe, or by the pipe moving through the water ; 
then let the mouth or end at which the water enters be fudden- 
ly flint by the machinery, and the water by its momentum 
will continue its motion relatively to the pipe, and will 
tend to exhauft the content of the pipe. This aftion will 
draw or fuck up water through the afcending-pipe from the 
lower level, fo as to fill up the vacuity in the main-pipe, oc- 
cafioned when the water therein perleveres in its previous 



The firft aud moft fimple hydraulic ram is /hewn in fec- 
tion at jig. 4. ( Plate Water-worhs ) ; here C C reprefents 
■■ the main-pipe, or body of the ram, through which the ftream 
•of current water is condufted ; D, the afcending-pipe pro- 
vided with a valve of exit at A, to allow the palTage of the 
water which is raifed, but to prevent its return ; B is a ftop- 
valve to clofe the end of tlie main-pipe ; E is a balance- 
weight fixed upon the lever G, which communicates with 
another, K, attached to the axis of the ftop-valve B ; this 
weight tends to open the valve at the proper time. The 
main-pipe is to be fituated in a current or ftream of water, 
either produced by the natural current or declivity of a 
river or other ftream, or by penning up the water by a dam 
or weir, and inferting the end of the main-pipe through the 
dam, fo as to obtain the greateft fall of water which the 
natural circumftances will admit of. To put the machine 
in aftion, let the ftop-valve be opened to the poiition (hewn 
in the figure, the water will run through the main-pipe C, 
until it acquires a certain velocity which will be propor- 
tioned to the height of the fall of water which produces 
the current of water. The aftion of the current upon the 
ftop-valve B, in its reclined pofition, will increaf* until it is 
fufficient to overcome the weight E, and then it will fliut 
the ftop-valve. The water being now fuddenly ftopped, 
and confined in the pipe C, by its impetus or momentum, 
will exert a confiderable force within the pipe, which will 
open the other valve A, and a portion of the water will 
rife up the afcending-pipe D. The force of the momentum 
being expended in raifing this water, the water in the main- 
pipe will immediately recover the equilibrium, and the 
clofing of the valve A will prevent the return of the water 
which is raifed in the afcending-pipe. The weight E now 
defcends, and opens the ftop-valve B, and the water in the 
main-pipe refumes its motion until its velocity is fufficient 
to clofe the valve A again, and the operation of raifing the 
water is again repeated. 

This water gradually rifes in the afcending-pipe until it 
reaches its fummit, and then a quantity will ifTue from it at 
every ftroke into a proper rcfcrvoir R. The quantity will be 
more or lefs, according as the height to which it is raifed, and 
to the velocity of the current, and the fize of the apparatus. 
In this defcription, we have taken no notice of the aftion of 
the air-veflel J, at the bottom of the afcending-pipe D, al- 
though its ufe is very important to the prafticability of the 
contrivance ; for where the water is to be raifed to any con- 
fiderable height, the pipes, although formed of the beft mate- 
rials that can be procured, will be in danger of rupture from 
the great concuffion of the water when fuddenly checked ; 
hence the rifing of the water would be limited to the height 
of a few feet, or the pipes muft be made of an extraordinary 
thicknefs, difregarding expence. 

This danger of burfting tlie pipes is to be regarded in 
every cafe of applying this invention to praftice ; but it 
Wfill be prevented, or very much diminiftied, by introducing 
an air-veifel I. The water from the main-pipe enters at 
every ftroke through the exit-valve A, and comprefles the 
air in the vefTel J, which again, by its expanfion or elafticity, 
afts upon the water, (which is prevented from returning to 
the pipe C by the ftiutting of the exit-valve,) and therefore 
rifes through the afcending-pipe, and by repeated ftrokes 
acquires the defired height. 

The dimenfions of the air-veflel, as well as its form and 
pofition, and whether it is afSxed to the main-pipe laterally 
<x above, are in a great meafure arbitrary ; but its contents 
of air ought not to be much lefs than ten times the quantity 
of water to be raifed through the afcending-pipe at each 

ftroke, and if very much larger ftill the better, the prin- 
cipal boundary being expence. 

The regulation of the ftop-valve B, is a principal point 
in the conftruftion of thefe machines. It may be opened 
and (hut by the current, as has been defcribed, in a very 
fimple manner, by adapting the valve to move upon an axle 
or liinge, and afliiling it to open at the proper time by a 
weight attached to a lever fixed to its axis at the proper 
angle. The valve fiiould be prevented from opening to 
fuch a degree, that the aftion of the current of water could 
not ftiut it. This muft be done by fome fixed refiftance be- 
hind the valves, as fhewn at B, jf^. 3, or by any other con- 
venient means. 

It is neceflary to adjuft the weight by experiment, fo as 
to open the valve at the right time, according to circum- 
ftances, which may be done either by Aiding the weight 
nearer to, or farther from, the centre of motion, or by in- 
creafing or dimini(hing the weight itftlf. The inconve- 
nience of this method is, that the weight being generally 
under water, it is troublefome to adjuft it ; therefore the 
mechanifm ftiewn in /fj. 4. is better adapted to the ftop- 
valve. The weight E is fitted upon a lever connefted with 
a fpindle, to which another arm or lever G is alfo fixed, 
and that is connefted by rod a, with the arm K fixed to the 

The rod may be prolonged to any necefTary length, and 
the weight and its machanifm may be always placed above 
water, io as to be eafily come at for adjullment. Valves 
of this kind may be hinged either upon their lower or 
upper edge, or upon one of the perpendicular fides as a 
common door, as convenience requires, and the mechanifm 
is connefted accordingly. 

When it is required to open the ftop-valve fo completely 
that the current of water in the main-pipe cannot aft upon 
it, to fliut it, a fmall ftream of water is led from the head, 
which fnpplies the main-pipe, or from fome other fource into 
a pipe or trough, which is furnilhed with a cock to regulate 
the quantity. This pipa or trough pours its water into the 
bucket G, Jig. 5, which caufes the bucket to preponderate, 
and by means of the lever he, fixed to its axle, and the 
rod cd attached to it, it ftiuts the ftop-valve B, by the con- 
neftion of the lever de attached to it. The bucket then 
empties its water, and the pendulous weight E, as foon as 
the recoil of the water in the main-pipe takes place,' prepon- 
derating in its turn, opens the valve, and reftores the bucket 
to its place. In this contrivance, by opening the cocks of 
fupply more or lefs, and by adapting the capacity of the 
buckets in proportion to the weight E, the number of ftrokes 
to be made in any given time is regulated. 

The ftop-valve may be conftrufted in a circular form, 
and, inftead of being hinged upon one fide, may be fixed 
upon a fpindle in its centre, which Aides in a focket, fimilar 
to what are called button-valves ufed in pump-work, and at 
the proper time is opened by mechanifm fimilar to the 
former ; or, in place of the weight, a fpring may be em- 

In conftrufting large machines, where the (hock, from 
(hutting the ftop-valve, might endanger the derangement of 
the machine, other kinds of ftop-valves will be preferable to 
thofe before defcribed. 

A very good form of valve is that which opens in two 
leaves, like the gates of a canal-lock. The leaves may (hut 
one upon another in the middle, or may (hut upon an up- 
right bar placed there. They are opened by the fame kind 
of mechanifm as we have defcribed before, only there muft 
be two connefting-rods, one to each leaf of the valve ; and 
4 th«fc 


th«fe b«og unitfd together, will caufe them to (hut both chine working 24 hour, wiU raife .34400 pints (French). or 

oanher^Th aperture for this vaWe i, of a reaangular 45,2 cub,c feet Engl'ff . of water to a he.ght of 15 f^t 

togecner. x ">- "f j ,j,j,[,_ -pj^p water railed by this machine is equal to f the 

A valve in two leaves, fuch as is called a butterfly-valve, power of a man, according to our ftandard. 
may alfo be hinged in the middle o 
too much obftruft the water-way. 

may^aifobe hinged in the middle of the opening, but would M. Montgolfier recommends the pipe or body of the ram 
^.^ nrh obftruA the water-way. When the mam pipe is to be of an equal diameter through the whole length ; and 

oT^a large rrte (for ikan'ce, two feet or upwards,) all internal irregularities are to be avoided, becaufe they 

IftopTalve may be made in three, four, or more leaves dimmifh the velocity of the water : the ftrength of the 

Snneaed together by mechanifm, f.milar to Veneuan win- (hou d be at leaft equal to fuftain a column of twice the 

COnneciea logcmc. u, height to which it is intended to raife the water. 

**°Inother kind of valve is poifed upon an axis, like a com- He fays, that he executed one with a fall of ,0 feet. 

inon fire-ftove chimney damper; the axis does not paf, which comprefred the air man air-vefTel to an equal degree 

S^ouffh its centre, but divides it into two unequal fegments. with 40 atmofpheres. which, taking the preffure of the at- 

The vTe is not opened fo far as to (land in the line of the mofphere equal to 33 feet of water makes the preffure 

current of water, but, when opened, ftands inclined to that equal a colunin of water . 320 feet m height 

cu^en ; fo that the larger fegment being placed towards Improved hydrauhc /J.m_-M Montgolfier, the fon of 

the ftream the latter may by its adion (hut it at the proper the uiventor, has recently obtained a patent in England for 

time It is opened by mechanifm fimilar to the former, an improved hydraulic ram, in which, by attention to fome 

Another kind of valve is a fpherical ball of porcelain, which minute particulars in the conftruaion he is enabled to make 

• fi T ft length of the tube much lefs than m the former ma- 

" When"th°e macMne is made ufe of in an open river, which chines ; and he has even obtained a refult equal to 84 per 

■ does not admit of having its water penned up by a weir or r.«^ of the power employed 

d^.head, the main pipe ought to be laid fo as to be covered One of thefe improvements is the addition of a fmall 

brthe low waters of the river ; and it ought to be parallel fnifting-valve, which, at each movement ferves to introduce a 

to the furface of the river, fo as to have the greatell poffible fmall quantity of air into the head of the ram, from whence 

dechvity that can be obtained in the length of the main it is driven by the next movement into the air-veirel, which 

pipe- its mouth or receiving end Ihould be (haped Uke that would otherwife become filled with water, if the air ab- 

of a trumpet or bell. In all cafes whatfoever, the valves forbed by the contad of the water under a ftrong preffure, 

oueht to be con,pletely under the furface of the water, in were not continually replaced by fome fuch means. 

vT I f Alfo, in the interior of the head of the ram is an annular 

' ^pTf^rmanTonL hydraulic Ram, (fee Ram ).-M. Mont- fpace, furrounding the frame of the ftop-valve : this con- 

.'J. . . ■'. , ■ r .!._. -i..i:__ I .i...,,i;r.,.o cvp. tams a fmall volume or air. which cannot be lorced into the 

fortieth part of the whole quantity which fell. He recom- that the water may flow more readily into the pipe ; and the 

mends particularly that the machine fhould be fixed in the length of the pipe muft be regulated according to the height 

moll fobd manner, by mafonry or timber, fo that the fliock of the fall of water, which is to produce the current through 

of the water can produce no motion of the machine, be- it. The pipe is conipofed of feveral pieces or lengths 

caufe all fuch motion will ded-.a confiderably from the fcrewed together by flanches, or other fimilar means ; but 

ouantitv of water raifed. It is Rated that the machine wiU >t is in the end piece, which is called the head of the ram, 

make from 20 to , 20 ftrokes per minute. that the moving parts of the machine are placed. 

The dimenfions of an hydrauhc ram at the bleaching The extremity of the pipe or head of the ram is a hollow 
works of M. Turquet, near Senhs, in France, when re- fphere, the diameter of which is nearly twice as great as the 
duced to Engli(h meafure, are as follow : diameter of the bore of this pipe : the upper part of the fpherical end is flat- 
body of the ram 8 inches, fall of the water 3 feet 4 inches, tcncd, fo as to reduce it to a fegment of a fphere, with a flat 
heiffhtto which the water is raifed 15 feet I inch. In three circular furfaceon the topor upper fide,in the centreofv^hich 

.6 .. .• 1 ni-i... ._i,;_u „~-,~„j„,i fiirfacp IS a larirc circular opening to receive and hold the 

?es, at which the water ilTues ; but v 
it prevents the water from iffuing. 
opens, it defcends perpendicularly 

feet= 140. Now -''^° is equal to ,Vjths, fo that the the hollow fphere, and leaves a free paffage through the 

' 223 opening. Its motion is guided between three or four per- 

effea produced is above fix-tenths of the power applied. In pendicular ftems, which have hooks formed at the lower 

another experiment it was found to be 64-hundrcdths. This ends to retain or fupport the valve when opened ; and thefe 

machine raifed a quantity of watercqual to 6.2 inches of water ftems are fixed by fcrews, fo that they can be regulated to 

(pooces de fontanier), for 269 litres which are nearly equal allow the valve to defccnd more or lefs, and open a greater 

to 280 pints, in three minutes ; and the pouce de fontanier or lefs pan"age for the water. The valve is made ofmetal, 

is a meafure of running water equal to 14 pints (French) and hollow, for it has a flat circular plate of metal, with a 

ter minate, or 796.37 cubic mches, Eoglifh. This ma- hollow cup or difti of metal attached to its lower furface : 

" this 


this at the fame time renders the valve hghter in the vpater, 
and gives it a convex furface on the lovper fide, which, wlien 
the valve is opened, correfponds in curvature with the in- 
terior concave furface of the fpherical end of the head of 
the ram. The feat of* the valve is compofed of a ftiort 
cylinder or pipe, of which the opening is much greater than 
the tranfverfe feftion of the body of the ram. This fhort 
cylinder is fcrewed by its flanch into the opening in the 
upper furface of the head of the ram. This flanch of the 
feat 18 fo formed as to have an inverted cup round the upper 
part of the fhort cylinder, that is, a circular channel or an- 
nular fpace within the head of the ram, which will contain 
air, and from which the air cannot efcape when the water 
comprefTes. The air in this channel is called the air- 

The fnifting-valve is at the end of a fmall pipe, which 
leads from the annular fpace or matrafs to the open air. 
The fnifting-valve opens inwards, in order to admit the air 
to enter into the matrafs ; but to prevent its return, there is 
another fmall valve in the fame pipe, which opens outwards : 
the office of this is to admit a certain quantity of air into 
the matrafs, and then to fhut and prevent any farther en- 

On the outfide of the feat of the ftop-valve that is over 
the aperture in the head of the ram, where the water iffues, 
another ftop-valve is applied, which is fimilar to the internal 
valve before mentioned, but fhuts down on the outfide of 
the feat. Its ufe will be hereafter explained. 

The upper part of the pipe or head of the ram is made 
flat at the part near the end where it enlarges to a fphere ; 
and this flat furface on the top of the pipe has feveral nar- 
row openings acrofs it, which are covered by as many flap- 
valves of leather, to allow water to pafs out from the main 
pipe, but to prevent its return. And on each fide of the 
head of the ram, at the part oppofite to thefe flap-valves, is 
a hollow enlargement, in form of a fegment of a horizontal 
circle ; and the two enlargements taken together form a 
circular bafon, through the centre of which the pipe of the 
ram paffes ; but, as before ftated, the pipe, inftead of being 
circular, is flat at top at that part, to form the feats for the 
flap-valves. This circular bafon is covered by a cylindrical 
air-veflel, fcrewed down by means of a flanch at the edge, 
fo that the circular bafon forms the bottom of the fpace in 
the air-veffel ; the flap-valves being covered by the_ air-veflel 
are therefore within the veflel. 

In confequence of this arrangement, all the water which 
iffues from the body of the ram through the flap-valves will 
flow off on each fide, and be received in the bafon ; but as 
the circular bafon or bottom of the air-veffel is divided into 
two parts, by the pipe of the ram which paffes through it, 
there is a palfage communicating from one of the enlarge- 
ments to the other ; for which purpofe, it curves down 
and defcends beneath the pipe of the ram ; and the afcend- 
ing pipe that carries away the water which the machine 
raifes, proceeds either from this curved paffage or from 
fome other part of the bafon, fo that it may receive the 
water which has paffed from the body of the ram through 
the flap-valves and the air-veffel into the bafon, at each fide 
of the pipe. 

The aftion of this hydraulic ram is nearly the fame as the 
preceding. Suppofe the pipe or body of the ram is full of 
water, if the internal ftop-valve is opened, the water from 
the refervoir will flow through the body of the ram, and 
iffue through the opening at the end, it will lift up the ex- 
;ternal ftop-valve and efcape ; but the current having con- 
tinued until the water has acquired a certain velocity, the 
force of the current buoys up the internal valve, and clofes 


the paffage. The motion of the water contained in the ram 
will thus be fuddenly arrefted, and by its -uw inertite, or 
moving force, will exert a fudden preffure againft the ftop- 
valve, and againft all the interior parts of the ram. The 
fmall quantity of air contained in the fpace around the 
interior ftop-valve, which is called the air-matrafs, is com- 
preffed into a fmaller fpace, and, by its elafticity, takes off 
the violence of the (hock or blow which would otherwife be 
produced. This preffure opens the flap-valves on the top 
of the pipe, which are within the air-veffel, and a portion of 
the water will be driven into the air-veffel, which is fup- 
pofed to be full of air, compreffed or condenfed, till its 
elafticity equals the preffure of the column of water which 
is to be raifed up the afcending pipe by the aftion of the 

The water which is forced into the air-veffel caufes the air 
therein to be condenfed, and to exert a greater degree of elafti- 
city, until it will exceed the preffure of the column of water 
in the afcending-pipe ; by degrees this air will therefore 
force through the faid pipe all the water which was injefted 
through the flap-valves, and caufe that quantity of water to 
iffue from the upper extremity of that pipe. 

The moving force, or v'ls inert'm of the mafs of wattr, 
which was in motion in the body of the ram, having expend- 
ed itfelf by forcing a portion of water into the air-veffel, and 
making a ftill greater compreffion of the contained air, a re- 
coil of the water in the body will take place with a flight 
motion from the valve towards the open end of the body ; 
this arifes from the reaftion or elafticity of the air contained 
in the air-matrafs, and alfo of the metal of which the tube 
is compofed. 

The flap-valves within the air-veffel fhut, and prevent the 
return of the water which has been forced into the air- 
veffel. This recoil of the water in the body towards the 
open end caufes a flight afpiration within the whole body of 
the ram, and the external ftop-valve defcends by its weight, 
and prevents the water with which it is covered from enter- 
ing through it ; but the air paffes through the fmall pipe, 
leading from the open air to the annular fpace or air-ma- 
trafs, and opens the fnifting-valve, and a fmall quantity of 
air is fucked into the matrafs ; but this is a very fmall 
quantity, becaufe the external air-valve clofes as foon as the 
air flows with a rapid current through the pipe and fnifting- 

During the recoil, the internal ftop-valve having nothing 
to fuftain falls by its weight, and opens the paffage ; and as 
foon as the force of the recoil has expended itfelf in afting 
againft the column of water contained in the refervoir at the 
open end of the body, the water begins again to flow 
through the body in its original direftion, and repeats the 
aftion before defcribed. 

It ftiuts the internal ftop-valve when it has acquired the 
intended velocity, and being thus ftopped, the efllux of the 
vis inertia condenfes the air-matrafs, and opening the flap- 
valves, forces a quantity of water into the air-veffel, from 
which the reaftion of the contained air will drive it up the 

The vis inertia of the moving column of water being thus 
expended, the recoil commences by the reaftion of the air in 
the matrafs, the flap-valves fhut, and the external ftop- 
valve likewife ; the afpiration produced by the recoil draws 
fome air through the fnifting-valve, and it joins the air in the 
matrafs. The internal ftop-valve falls open by its weight 
and opens the paffage, fo that the water in the pipe can re- 
fume its motion when the recoil has exhaufted itfelf. 

The fmall quantity of air which is drawn into the ma- 
chine through the air-valve, at each afpiration, caufes an ac- 
K. cumulation 


cumulation of air in the matrafs ; and when thf afpiration 
of the recoil takes place, a fmall quantity of this air paffes 
from the annular fpace, and proceeds along the pipe till it 
arrives beneath the flap-valve, and lodging in the fmall ipace 
beneath thcfe valves, it will be forced into the air-vcfTel at 
the next llrokc, by which means the air-veffel is always kept 
filled with air. 

The following are the dimenfions of a machine which is 
calculated to raife water up the tube to i oo feet above the 
f urface of the water in the refervoir, when the fall by which 
it is worked is five feet, that is, where the level of the water 
in the refervoir is five feet above the lower level ; and the 
length of the pipe from the open end to where the water is 
difchargcd is to be twenty feet long, and fix inches in 

Such a machine may be expeAed to expend about feventy 
cubic feet per minute to work it, and to raife up about two 
and one-third cubic feet per minute ; but thefe quantities 
cannot beexaftly ftated, becaufe they depend upon the care 
and accuracy with which the machine is conftrufted. 
Under different circumftances, having a greater or lefs 
fall or quantity or water, the dimenfion of the machine 
muft be calculated accordingly. 

The improvements in this laft form of the hydraulic ram 

Firft, that by conftrufting the head of the ram with the 
upper fide of the pipe flat, and applying the flap-valves im- 
mediately upon the top, there is very little fpace to contain 
dead water, that is, water which will be motionlefs when the 
current takes place in the pipe ; and by dividing the fingle 
valve of the original machine into feveral fmall and narrow 
valves, they open and (hut more fuddenly, and with lefs lofs 
of water. 

Secondly, in making the bafon on each fide of the pipe, 
which bafon is on a lower level than the flap-valves. 
By this means the water will flow off from the flap-valve on 
each fide, and at the inftant when the machine performs its 
ftroke, and forces water through the faid valves into the air- 
▼efTel, the valves will not be covered, or at leail very flightly 
covered by water ; confequently, when thofe valves open, and 
the water is forced into the air-veffel, it has only the com- 
preffed air to oppofe it, which from its elafticity allows the 
water to enter with more facility than if it was refilled by a 
column of water refting upon the valves ; not tliat there is any 
lefs hydroftatic preffure upon the valves, becaufe it is the air 
which bears upon them, inftead of the water, but there is a 
lefs mafs of matter to be put in motion by the water which 
enters into the air-veflcl : for it has only the matter con- 
tained in the valves themfelves to put in motion. 

Thirdly, in applying the external flop-valve, the ufe of 
which is to prevent the water returning into the ram when 
the recoil takes place, and having this provifion, a greater 
quantity of air can be employed in the matrafs than could 
otherwife conveniently be done ; this renders the (hock 
which takes place when the Hop-valve is (hut lefs fudden. 
We have examined feveral of thefe machines made in France 
by the inventor, aiid can with confidence recommend them 
to engineers as the very beft machine, and the molt fimple 
for raifing water when there is a natural fall. The laft im- 
provements, as they enable us to (horten the length •f the 
body of the ram to nearly one-third, without reducing the 
performance, are very important. 

The hydrauUc ram is adapted to give motion to the hy- 
droftatic prelfes, which are in common ufe under the name 
of Bramah's pre(ros. For this purpofe, it is only ncccfTary 
to apply the afcending-pipe to th? cyhnder of the hydr.iulic 
prefi, and at each ftrolte of the ram a fmall quantity of 

water will be forced or injefted into the cylinder of the 
prefs, and will thus produce the afcent of the pifton of the 
prcfs in the fame manner as is now performed by the fmall 
injeftion-pump worked by the force of men. But by the 
application of the hydraulic ram to that purpofe, the prefs 
can be worked in any fituation where there is a fmall fall of 
water, and the ram may be fet in motion whenever the prefs 
is wanted. 

An HydrauUc Ram, or Momentum Machine ading by SuSion, 
is (hewn 3tfigs. 2 and 3. Plate IVater-'woris. This is appli- 
cable in cafes where the water to be raifed is below the level 
of the main-pipe, and is to be difcharged at that level ; a cafe 
which frequently occurs in the drainage of marfhy lands, 
where the aftion of the current of water, in an embanked 
river, or other ftream or fource of water on a higher level, 
can be employed ; or this method can be applied in raifing 
water out of the holds of (hips by the motion of the veftel 
through the water ; alfo to raife water out of a well of mo- 
derate depth. 

C reprefents a portion of the main-pipe ; "Sitjig. 2. is 
the ftop-valve fituated at the entrance of the pipe, and open- 
ing outwards fo as to ftop the palfagc of the pipe when it is 
(hut ; D, the afccnJing or fuckiiig-pipe, communicating 
with the well at the bottom and with the main-pipe at the 
top ; J is the air-veffel ; and E the weight of the flop-valve 
of the main-pipe. There is likcwife a valve A opening 
from the air-veffel into the main-pipe. 

The water in the main-pipe having acquired a proper ve- 
locity by the current, as in the former cafes, the ftop-valve 
B (huts, and the water in the main-pipe continuing its mo- 
tion for a time, draws air out of the air-ve(rel J, through the 
valve A. The momentum of the water in the main-pipe 
being foon expended it recoils, the receiving-valve A (huts 
to prevent the return of the water into the air-veffel, and the 
ftop-valve B opens by the aClion of the weight E, the water 
thus regains its paflage, and foon acquires fufficient ve- 
locity to clofe the ftop-valve again, and the operation is 

Thus in a few ftrokes the exhauftion is increafed till the 
air-veffel fucks up water from below, through the afcending- 
pipe D, or ratlier the preffure of the atmofphere on the fur- 
face of the valve below forces it up, when the prelfure on 
the furface within the air-veffel is removed by the ex- 
hauftion. This atlion being continued, the afcending-pipe 
fills by degrees to the top, after which, at every fuccelUve 
llrokc, a portion of the water from below pafies into the 
main-pipe, and is carried off into the pipe C, where it mixes 
with the upper water. 

In cafes where the water of the tide or other alternating 
current is employed as the motive power, the apparatus may 
be conftrufted in two ways, eitiier by applying a ftop- 
valve, air-veffel, and afcending-pipe, fuch as is (hewn at one 
end in_y^. 4. to each end of the main-pipe C, to be ufed al- 
ternately, according as the tide fets in the one direftion or 
the other ; or otherwife by applying two main pipes to one 
air-veffel, their mouths being placed in oppofitc direftions 
and to be ufed alternately, and applied to the raifing of water, 
for the ufe of falt-works, or for other ufes, fuch as the fup- 
ply of a country -houfc. 

The firft machine above defcribed may be employed to 
raife water to fmall heights by the motion of the waves of 
the fea,.or of any large pieces of water ; in which cafe the 
mouth or receiving end of the main-pipe fhould be formed 
like a fpeaking-trumpet, as fhewn \njig. 4. and placed op- 
pofite to the direftion in which the waves beat upon the 
ihorc at the place where tiie machine is. The water of tlie 
waves will enter the main-pipe, and rufh through it until 



tite ftop-valve (huts ; when the contained -water will in part 
enter the air-veflel by the aftion already defcribed, and the 
next wave will produce another ftroke. 

Momentum- Pump, or Momentum- Machine, to ra'tfe Water 
by the application of mechanical Ponver. — Where a fall of 
water cannot be obtained,_/?f. i. fhews an application of this 
njomentum principle, in lieu of pumps for raifing water, the 
main-pipe being put in motion through the water by the 
ftreugth of men, or other mechanical power in default of a 
current, as in the other cafes. 

C C is the main-pipe bent in a fpiral form round the air- 
veflel J ; it may either be made to touch it, or be kept at a 
diftance from it, and may make one or more revolutions 
round the faid veflel; the whole of the main-pipe is im- 
merfed in the external water which is to be raifed. Both 
ends of the pipe are open to the water ; but one of them 
has the ftop-valve opening inwards, which will occafionally 
clofe it, and near this latter end, a communication is made 
by a fide-pipe with the air-veflel, the orifice being covered 
by a valve opening into the veflel. The whole turns upon 
3 pivot K, at the lower end of the afcending-pipe D, which 
ferves as an axis, and is kept upright by a collar, in which it 
turns, as fliewn at L. Upon this axis a toothed wheel M 
is fixed, and is put in motion by another wheel N, turned 
by a winch, crank, or other contrivance. 

At the top, or upper end of the afcending-pipe, the 
water is difcharged into a trough, which furrounds it, and 
conveys it to the place of its deftination. 

This apparatus is made to raife water by a continued ro- 
tative motion, the open end moving firft, through the water 
which pafles out again through the other end ; but whenever, 
by that motion, the main-pipe has attained a proper velo- 
city, the ftop-valve fliuts fuddenly, and by the concuflion 
the water pafles into the air-veflel, from whence the egrefs 
of the water is prevented by the (hutting of the exit-valve. 
The ftop-valve then opens by means of a fpring in lieu of a 
weight, as in the former cafes, and the apparatus continuing 
to revolve in the fame direftion, more ftrokes are made at 
intervals proportioned to the velocity with which it moves. 
The fpring of the ftop-valve ftiould he fo regulated in force 
as to allow the relative motion of the water in the main-pipe 
to ftiut the ftop-valve at proper intervals. The perpen- 
dicular feftion of the main-pipe is drawn fquare, but may 
be circular, or of any other convenient figure. A horizontal 
fedion of it is fliewn ztjig. 6, with the main-pipe and the 

In lieu of the wheel N, which produces a continued 
rotatory motion, the machine may be made to vibrate or 
fwing upon an axis, backwards and forwards, the hmits of 
the vibration or ftroke being determined by a detent ftriking 
againft a ftiff fpring. In this cafe, the main-pipe fhould 
be provided with ftop-valves at both ends, and alfo have a 
communication at each end with the air-veflel, which open- 
ings fliould be clofed by valves to prevent the return of the 
water from it. Such a machine may be put in motion by 
the following means : upon the afcending-pipe D, a double 
pulley is fixed, round which are wound the ropes, and by 
pulling the ends of thefe alternately, the apparatus may be 
made to revolve in either dire£lion. The main-pipe and 
the afcending-pipe being filled with water by hand or 
otherwife, if the ropes are pulled alternately, they wiU 
make the pipe move through the water with fufficient velo- 
city to make the apparatus aft. It is found if the appa- 
ratus makes about thirty vibrations in each minute, that it 
will aft very completely. 

Hydraulic machines are of the greateft importance to 
fociety, whether we look to a fupply of the firft necefiity 

for domeftic ufes, or to the advantageous ufes of neglefted 
though valuable firft movers. Thefe machines muft, in moft 
cafes, be modified by localities, and other circumftances ; 
and confequently the moft ufeful praftical knowledge will 
not confift in any acquaintance with, one or more of the beft 
engines, but with that great variety of happy contrivances 
which inquiry and refleftion muft point out. We have, as 
far as our limits permit, given aU the machines which are 
praftically ufeful, and we (hall conclude this article by 
giving Dr. Young's catalogue of the moft important and 
valuable writings on hydraulic engines. 

Ramelli's Colleftion of Hydraulic Machines, in French 
and Itahan, 1588, folio. 

Defcriptio Machina: Hydraulics curiofs Conftrufta, 
Joh. Georg. Faudieri, Venet. 1607. 

Bates on Art and Nature, 1635. 

Nouvelle invention de lever I'eau plus haut que la fource 
avec quelque machines mouvantes par le moyen de I'eau, 
&c. par Ifac de Caus, 1657. 

Jofephi Gregorii a Monte Sacr. Principia phifico-mecha- 
nica diverfarum machinarum feu inftrumcntorum pneumatics 
ac hydrauhces, Venet. 1664. 

Nouvelle Machine HydrauHque, par Francini Journ. des 
S^av. 1669. 

I^An account of this machine is likewife given in the 
Architefture HydrauHque of Belidor, torn. ii. ; and in the 
2d vol. of Defaguliers' Experimental Philofophy : in both 
which performances many other hydrauhc machines are 
defcribed. j 

An Undertaking for raifing Water, by Sir Samuel More- 
land. Phil. Tranf. 1674. N° 102. 

An Hydrauhc Engine. Phil. Tranf. 1675. N°i28. 

A cheap Pump, by Mr. Conyers. Phil. Tranf. 1677. 
N" 136. 

M. de Hautfeuille, Reflexions fur quelque Machines a 
elever les eaux, avec fa defcription d'une nouvelle pompe, 
fans frottement, et fans pifton, &c. 1682. 

Elevation des eaux par toute forte des Machines, reduite 
a la mefure, au poids, a la balance, par le moyen d'un nou- 
veau pifton et corps de pompe, et d'un nouveau mouvement 
cyclo-elliptique et rejetant I'ufage de toute forte de mani- 
velles ordinaires, par le Chevalier Morland, 1685. 

A new Way of raifing Water, enigmatically propofed 
by Dr.Papin. Phil. Tranf. 1685. N'' 173. The folu- 
tions by Dr. Vincent and Mr. R. A. in N° 177. 

M. du Torax, Nouvelles Machines pour Spuifer I'eau 
des foundations, qui, quoique tr^s fimples font un effet 
furprennant, 1695. Joun. des S^av. 1695. p. 293. 

An Engine for raifing Water by the help of Fire, by 
Mr. Thomas Savery. Phil. Tranf. 1699. N° 253. 

D. Papin nouvelle maniere pour lever I'eau par la force 
du feu ; a Caifel, 1707, 

Memoire pour la conftruftion d'une pompe qui fourni 
continuelment de I'eau dans le refervoir, par M. de la Hire, 
Mem. Acad. Scien. Paris, 1716. 

Defcription d'une machine pour elever des eaux, par M. 
de la Faye, Mem. Acad. Scien. Paris, 1717. 

Joh. Jac. Bruckmann's und Joh. Heinr. Weber's Ele- 
mentar-mafchine oder univerfal-mittel bey alien waffer-hebun- 
gen. Ca(rel, 1725. 

Jacob Leopold, Theatri machinarum hydraulicanim, 
1724 et 1725. 

Joh. Prid. Weidleri traftatus de machinis hydraulicis 
toto terrarum orbe maximis Marlyenfi et Londinenfi, &c. 
1727. Vide Aft, erudit. Lipf. 1728. 

A Defcription of the Water-works at London-bridge, 
by H. Beighton, F. R. S. Phil. Tranf. 1731, N°4i7. 

K 2 An 


Au account of a new engine for raifing water, in which 
horfes or other animals draw without any lofs of power 
(which has never yet been praftifed) ; and how the ftrokes 
of the pifton may be made of any length, to prevent the 
lofs of water by too frequent opening of valves, &c. by 
Walter Churchman. Phil. Tranf. 1734. 

Sur I'effet d'une machine hydraulique propofee, par M. 
Segner, par M. Leon. Euler. Mem. Acad. Scien. Ber- 
lin, 1750. 

Application de la machine hydrauhque de M. Segner, a 
toutes fortes d'ouvrages et de fes avantages fur les autres 
machines hydrauliques, par M. Leon. Euler. Mem. Acad. 
Scien. Berhn, 175 1. 

£M. Segner's machine is no other than the fimple yet 
truly ingenious contrivance known by the name of Barker's- 
mill, which has been defcribed in the 2d volume of Defa- 
guliert' Philofophy, fome years before the German pro- 
leflbr made any pretenfions to the honour of the invention. 
The theory of it is hkewife treated by John Bernouilli at 
the end of his Hydraulics.] 

Recherches fur une nouvelle mani^re d'elever de I'eau 
propofee, par M. de Mour, par M. L. Euler. Mem. Acad. 
Berlin, 1751. 

Difcuffion particuli^re de diverfcs manieres d'elever de I'eau 
par le raoyen des pompes, par M. L. Euler. Mem. Acad. 
Berlin, 1752. 

Maximes pour arranger le plus avantageufement les ma- 
chines dellinees a elever de I'eau par le moyen des pompes, 
par M. L. Euler, Mem. Acad. Ber. 1752. 

Refli'Aioi.s fur les machines hydrauliques, par M. le 
Chevalier D'Arcy, Mem. Acad. Scien. Paris, 1754. 

Memoires fur les pompes, par M. le Chevalier de Borda, 
Mem. Acad. Scien. Paris, 1768. 

Dan. BernouiUi, Expofitio theoretica fingularis machinx 
hydraulics. Figuris helvetiorum exftruftse. Nov. Com. 
Acad. Petrop. 1772. 

Abhandlungen von der Waflerfchraube, von D. Scherffer, 
Priefter Wien. 1774. 

Recherches fur les moyens d'executer fous I'eau toutes 
fortes de traveaux hydrauliques, fans employer, aucunepuife- 
ment, par M. Coulumb. 1779. 

Saemund Magnuffen, Holra, Eftarretning om llcye pum- 
pen Kiobenhavn, 1779. 

Moyen d'augmenter la vitelFe dans le mouvement de la 
▼ig d'Archimede fur fon axe, tire des memoires manufcrits 
de M. Pingeron, fur les arts utiles et agreables. Journ. 
d'Agric. Juin. 1780. 

Tiie Theory of the Syphon, plainly and methodically 
illu'ftrated, 1781. (Richardfon.) 

Memoria fopra la nuova tromba funiculare umihata, dal. 
Can. Carlo. Caftelli. Milano, 1782. 

DifTertation de M. de Parcieux fur le moyen d'elever 
I'eau par la rotation d'une corde verticale fans fin Amfter- 
dam et Paris, 1792. 

Theorie der Wirzichen fpiral pumpe erlaiitert von Heinr. 
Nicander, Schwed, Abhandl. 1783. 

Jac. Bernouilli, Eflai fur une nouvelle machine hydrau- 
lique propre a elever de I'eau, et qu'on pent nommer 
machine pitotienne. Nov. AA. Acad. Petrop. 1786. 

K. Cli. Langfdorf's Borechnungcn iiber die vortheil- 
hidtere benutzung angclegtcr fammeltciche zur betreibung 
der mafchinen. AA. Acad. Elcft. Mogunt, i784,'i785. 
Nicander's Theorie do fpiral pumpe, 1789. 
Nouvelle architedture hydraulique, par M. Prony, 1790, 

A fliort account of the invention, theory, and prafticc of 
fire-machinery ; or iiitrodu£tion to the art of making ma- 

chines, vulgarly called fteam-engines, in order to exfraft 
water from mines, convey it to towns, and jtts d'eaux iir 
gardens, to procure water-falls for fuUing, hammering, 
ftamping, rolling, and corn-mills, by William Blakey, 1793- 

Machines aduated by the Force of Currents or Streams of 
Water. — Thefe are very numerous, but all may be reduced 
to two kinds. 

Firft, thofe which are adapted to receive the impulfe of 
moving water ; that is, water which has been put in motion 
in confequence of a defcent towards the earth previoufly to 
its operating on the machine, which muft be provided with 
parts proper to refill and take away fome of the motion of 
fuchjwater, and it will thereby receive motion which may be 
applied to produce fome mechanical efTeft. Of this kind ajre 
underfhot and horizontal water-wheels. 

Secondly, thofe machines which are provided with fome 
kinds of buckets or velTels to contain water, the weight of 
which buckets, and the water they contain, is fupported by 
the machine, fo that the water cannot defcend towards the 
earth in confequence of its gravitation, without giving mo- 
tion to the buckets or veflels which contain and fupport it. 
Of this kind is the over-(hot water-tvheel, breail-wheel, 
chain of buckets, and prelTure-engine. 

In either cafe, the motive force or power is the fame ; 
vi'z. the gravitation and motion of fuch bodies or mafles of 
water as are found more elevated above the furface of the 
earth than the general level of the fea, or of fome other 
water in its neighbourhood ; fuch water will defcend by the 
force of gravity until it joins the fea, or until it is fupported 
or held up by fome fixed obftacle. 

The difference between the two kinds of machines is, that 
in the firft cafe the water is f offered to defcend before it 
operates upon the machine, and in confequence of its gra- 
vitation, acquires motion with a velocity proportioned to 
the fpace tlu-ough which it has defcended ; and the office 
of the machine is to take from the moving water as much 
of its compounded weight and motion, or power, as it can 

In the other cafe, the machine receives its motion and 
power at the fame time, when the water acquires it, by de- 
fcending ; or, in other words, the machine moves with the 

The word power, as ufed in pra£lical mechanics, fignifies 
the exertion of flrength, gravitation, impulfe, or prefTure, 
fo as to produce motion ; and a machine aftuatcd by means 
of ftrength, gravitation, impulfe, or prcfTure, compounded 
with motion, is capable of producing an effeA : and no 
effetl: is properly mechanical but what requires fuah a kind 
of power to produce it. 

The mufcular power of animals, as likewife prefTure, im- 
paA, gravity, clcftricity, &c. are looked upon as forces, 
or fources of motion ; for it is an incontrovertible fadl that 
bodies expofed to the free aftion of either of thefe are put 
in motion, or have the ftate of their motion changed. All 
forces, however varion.s, can be meafured by the cfTefts they 
produce in like circumllances ; whether the eflefls be 
creating, accelerating, retarding, or dcflcAing motions : 
the effeft of fome gentral and commonly obferved force is 
taken as unity. 

The moft proper meafurc of power is the aft of raifing 
fome weight with fome velocity of motion ; that is, the 
overcoming of the gravitating force of a weight in fuch de- 
gree as to produce motion in oppofition to gravity. In 
confidering the quantum, the weight or mafs of matter 
operated upon muft be one quantity, and the velocity of the 
motion communicated is the otlier ; the mechanical power is 



ihe compound of both. We can only meafure the weight 
of any body or mafs of matter by its relation to fome other 
weight with which we are acquainted ; hence we fay, the 
weight is equal to fo many pounds, or fo many cubic feet of 
water. In like manner, we meafure the velocity or intenfity 
of the motion, by ftating the height or perpendicular dif- 
tance from the earth, (meafured by relation to fome known 
diflance, as a foot or a yard,) through which height the 
weight is raifed in fome known fpace of time, as a fecond or 
a minute. 

For inftance, 528 cubic feet of water is a known weight 
or mafs of water : let a machine operate upon this, and raife 
It upwards, through the fpace of one foot in the time of 
one minute ; then 528 x i x i = 528 is the number 
which reprefents the power which the machine exerts. Sup- 
pofe another machine to operate on 132 cubic feet of water, 
and raife it four feet in one minute, then ufing the fame 
meafures to determine the quantities of weight, height, and 
time, we fay 132 x 4 x i = 528 ; hence thefe two ma- 
chines are equal in the power which they exert ; for in all 
cafes the weight raifed is to be multiplied by the height to 
which it can be raifed in a given time, and the produft is the 
meafure of the power expended in raifing it ; confequently, 
all thofe powers are equal whofe produfts made, by fuch 
multiplication, are equal ; for example, take two powers, 
if one can in any given time raife twice the weight to the 
fame height, or the fame weight to twice the height, in the 
fame time that the other power can, the firft power is 
double the fecond ; or, if one power can raife half the 
weight to double the height, or double the weight to half 
the height, in the fame time that another can, thofe two 
powers are equal : but note, all this is to be underftood 
only in cafes of flow or equable motion of tlie body raifed, 
for in quick, accelerated, or retarded motions, the vis iner- 
t't£ of the matter moved will make a variation. 

The machines aAuated by the impulfe of flowing water 
are, the underfhot water-wheel, horizontal wheels, and Dr. 
Barker's mill. It is a common exprefllon to call all wheels 
in which the water runs or (hoots under the wheel, under- 
fhot ; but in this place we fhall only fpeak of 

Umkrjhtt Wattr-Wheeh, ad'ing by the Impulfe of Jlowing 

Water Thefe are the moft ancient and original forms 

of water-machines, although if they had been invented from 
the refult of reafoning, fuch as we have given, they would 
have been the laft, becaufe their manner of aftion is lefs 
obvious ; but this was not the cafe. The firft machines 
were wheels placed in a river or running ftream, and pro- 
vided with vanes or wings on the circumference, called 
floats; the floats at the lower part of the wheel, dipped into 
the ilream to intercept the water. When the plane of the 
floats became perpendicular to the direftion of the current, 
or nearly fo, they would refill or oppofe the motion of the 
water, and the wheel would obtain motion from it in pro- 
portion to the quantity of motion, its floats abftrafted from 
the water of the flream. The power thus obtained would be 
found to be only a fmall proportion of the power of the 
ftream, becaufe the water would eafily efcape fuleways from 
the floats, parti culai-ly if it were attempted to take away any 
confiderable fliare of the velocity of the water, by refilling 
or loading the wheel, fo as to make it move flowly. Hence 
it became an obvious improvement to contradl the river to 
the exaft fize of the float-boards of the wheel, or to make 
a clofe channel in which the wheel exaftly fits. The next im- 
provement would be to intercept the river or ftream of 
water by a dam, or obftacle, in order to make it pen up, or 
accumulate, till it had rifen to the greateft height which 
could be obtained, and to let the water out of the dam or 

refervoir into the channel or wheel-courfe, through a verti- 
cal aperture or door, level with the bottom of the wheel- 
courfe ; in this way, the water would be urged by the pref- 
fure of the water in the dam, and would rufli out from the 
aperture in a dream or Ipout, with a velocity proportioned 
to the perpendicular prefliire, and would ftrike the float- 
boards of the wheel fo as to urge them forwards. Such is 
the form of the underfliot wheels ftiU generally employed in 
France and on the continent ; but in England they have 
been long fuperfeded by more effeftual applications of the 
power of the water, and it is very rarely we meet with 
an underlhot wheel afting by the impulfe of the water. 
They are called ground-lhot wheels, becaufe the water runs 
or flioots along the ground or floor of the channels in which 
the wheels work. 

It was firfl proved by Mr. Smeaton, in 1754, that 
only a portion of the power of any fall of water could be 
obtained by means of an underfliot wheel ; for M. Beli- 
dor had not long before ftated the underfliot wheel as the 
bed mode of applying a fall of water. It was one of the 
continual occupations of Mr. Smeaton, during forty years, 
to improve the old water-mills, by fubllituting breaft-wheels 
for underfliot ; and the advantages were uniformly fo great, 
that thefe mills were copied by others, until fcarcely any of 
the original conftruftion remained. We do not mean that 
Mr. Smeaton invented the breaft-wheel, for it is defcribed by 
Leopold ; but he firll inveftigated its comparative ad- 

It is from this circumftance that we find, in all the mecha- 
nical writings of foreign authors, much more mathematical 
invelligation relative to the underfliot water-wheels than the 
importance of the fubjeft deferves, and we fliall difmifs it 
more briefly. 

The excellent paper by Mr. Smeaton, in the Philofopbi- 
cal TranfaAions for 1759, contains a numerous lifl: of expe- 
riments moft judicioufly contrived by liim, and executed 
with the accuracy and attention to the moft important cir- 
cumftances which are to be obferved in all that gentleman'* 

Mr. Smeaton's rules were originally deduced from expe- 
riments made on working models, which are the beft means 
of obtaining the outlines in mechanical enquiries ; but in 
every cafe it is neceffary to diftinguifli the circumfl;ances in 
which a model difl"ers from a machine at large, otherwife a 
model is more apt to lead from truth than towards it ; and 
we muft not, without great caution, transfer the refults of 
fuch experiments to large works. But we may fafely tranf- 
fer the laws of variation, which refult from a variation of 
circumftances, although we mufl; not adopt the abfolute 
quantities of the variations themfelves. Mr. Smeaton was 
fully aware of the limitations to which conclufions drawn 
from experiments on models are fubjeft, and has made the 
applications with his ufual fagacity. The befl; ilrufture of 
machines cannot be fully afcertained but by making trials 
with them, when made of their proper fize. 

Mr. Smeaton's Principles for Underfhot Wheels.— \n com- 
paring the effeft produced by water-wheels with the powers 
producing them ; or, in other words, to know what part of 
the original power is neceflarilylodin the application, we mufl 
previoufly know how much of the power is fpent in overcom- 
ing the fnftion of the machinery, and the reiiftance of tlie 
air ; alfo, what is the real velocity of the water at the in- 
itant it ftrikes the wheel ; and the real quantity of water 
expended in a given time. 

The velocity Mr. Smeaton meafured in a moft fatisfaftory 
manner in every experiment, by applying a cord and weight 
to the axle of the wheel, not to wind up the weight by the 



motion of the wheel, but that the weight by dercending 
fliould turn the wheel. He applied fo much weight as would 
make the wheel turn, and make its floats move with the ve- 
locity which he deftred or expefted the effluent water to 
have ; and this weight he adjufted until he found, by re- 
peated trials, that the wheel moved juil at the fame rate, 
whether the water was fuffered to flow and ftrike its floats, or 
whether the water was flopped, whicli proved that the floats 
of the wheel moved with prccifely the fame velocity as the 
effluent water ; then bv mcafuring the circumference of the 
wheel, and counting the number of turns it made in a mi- 
nute, he obtained the meafure of the velocity. 

From the velocity of the water at the inllant that it 
ftrikcs the wlieel, the height of head pi-oduftive of fuch 
velocity can be deduced from acknowledged and experi- 
mented principles of hydroftatics ; fo that by multiplying 
the quantity or weight of water really expended in a given 
time by the height of a head fo obtained, whicli mull be 
confidered as the effeftive height from which that weight of 
water had defcended in that given time, we fl»all have a pro- 
duft equal to the original power of the water, and clear of 
all uncertainty that would arife from the friftion of the water 
in pafling fmall apertures, and from all doubts arifing from 
the different meafure of fpouting waters, afligned by dif- 
ferent authors. 

On the other hand, the fum of the weights raifed by the 
adlion of this water, and of the weight required to over- 
come the friftion and refiftance of the machine, multiplied 
by the height to which the weight can be raifed in the time 
given, the produft will be equal to the efFeft of that 
power ; and the proportion of the two produfts will be the 
proportion of the power to the effeft : fo that by loading 
the wheel with different weights fuccefTively, we fhall be 
able to determine at what particular load and velocity of the 
wheel the efFeft is a maximom. 

From experiments condufted in this manner, Mr. Smea- 
ton fettled the following maxims : 

Maxim I . That the virtual or effective head of water, and 
confequently its effluent velocity being the fame, the mechani- 
cal effeft produced by a wheel aftuatcd by this water will 
be nearly in proportion to the quantity of water expended. 

Note. The virtual or effeftive head of any water which is 
moving with a certain velocity, is that height from which a 
heavy body mufl fall in order to acquire the fame velocity. 

The height of the virtual head, therefore, may be eafily 
determined from the velocity of the water ; for the heights 
are as the fquare of the velocities ; and the velocities, con- 
fequently, as the fquare roots of the heights. Mr. Smea- 
ton obferved the velocity of the effluent water in all his ex- 
periments, and thence calculated the virtual head ; he flates 
that the virtual head bears no proportion to the real head or 
depth of water ; but that when either the aperture is 
greater, or when the velocity of the water iffiiing therefrom 
lefs, they approacii nearer to a coincidence ; and confequently, 
in the large openings of mills and fluices, where great quan- 
tities of water are difcharged from moderate heads, tlie 
aftual head of water, and the virtual head, as determined by 
theory from the velocity, will nearly asjree. 

For example of the application of his firft maxim. Sup- 
pofe a mill driven by a fall of water, whofe virtual iiead is 
5 feet, and which difcharged 550 cubic feet of waterier 
minute ; and that it is capable of grinding four buflicls of 
wheat in an hour. Now another mill, having tlie fame vir- 
tual head, but which difcharges iioo cubic feet of water 
fer minute, will grind eight bufhcls of corn in an hour. 

Maxim 2. That the expcnce of water being the fame, the 
effeft produced by an undcrlhot wheel will be nearly in pro- 

portion to die height of the virtual or effeftive head. This 
is proved in the prxreding example. 

Maxim 3. Tiiat the quantity of water expended being the 
fame, the effeft will be nearly as the fquare of the velocity 
of the water ; that is, if a mill driven by a certain quantity 
of water, moving with the velocity of 18 feet per fecond, 
is capable of grinding 4 bufhels of com in an hour, another 
mill, driven by the fame quantity of water, but moving 
witli the velocity of 22^ {i:et per fecond, will grind nearly 
7 bufliels of corn in an hour ; becaufc the fquare of 18 is 
324, and the fquare of 22i is 506^:. Now fay, as 324 
IS to 4 bufhels, fo is 5CO5 to 6f bufhels ; that is, as 4 
to 6i. 

Maxim 4. The aperture through which the water ifTues 
being the fame, the effeft will be nearly as the cube of the 
velocity of the water iffuing ; that is, if a mill driven by 
water rufliing through a certain aperture with the velocity 
of 18 feet ^^>- fecond will grind 4 bufhels of corn in an 
hour, another mill, driven by water moving through the 
fame aperture, but with the velocity of 22^ teet per fecond, 
will grind 51 bulhels ; for the cube of 18 is 5832, and the 
cube of 22^ is 11390!^; theo, as J832 is to 4, fo is 

Masim 5. The proportions between the powerof the water 
expended, and the effeft produced by the wheel, was 3 to 1. 
Upon comparing feveral experiments, Mr. Smeaton fixed the 
proportions between them for large works ; that is, if 
the weight of the water which is expended in any given 
time bt multiplied by th • height of the fall, and if the 
weight raifed be alfo multiplied by the height through 
wliich it is raifed, the firfl of thefe two produfts will be 
three times that of the fecond. 

Maxim 6. The bcfl general proportions of velocities 
between the water and the floats of the wheels will be 
that of 5 to 2 ; for inflance, if the water when it flrikes 
the vviieel moves with a velocity of eighteen feet f>er 
fecond, the wlieel mufl be fo loaded that its float-boards 
will move with a velocity of 7.2 feet per fecond, and the 
wheel will then derive tlie greatefl; power from the water, 
bccaufe as 5 to 18, fo is 2 to 7.2. 

Maxim 7. There is no certain ratio between the load 
that -the wheel will carry when producing its maximum of ef- 
feft, and the load that will totally flop it ; but it approaches 
ncarefl to the ratio of 4 to 3, whenever the power exerted 
by the wheel is greateft, whether it arifes from an in- 
creafe of the velocity, or from an increafed quantity of 
water ; and this proportion feems to be the moll applicable 
to large works. But when we know the effeft a wheel 
ought to produce, and the velocity it ought to move with 
whilfl producing that effeft, tlie cxaft knowledge of the 
greateft load it will bear is of very little confequence in 

Maxim 8. The load that the wheel ought to have, in order 
to work to the moll advantage, can be always affigned thus: 
afcertain the power of the wIkjIc body of water, by multiply- 
ing the weight of tlie water expended in a minute by the height 
of the fall, take one-third of the produft, and it gives the 
effeft of power which the wheel ought to produce : to find 
the load, we mufl divide this produdl by the velocity which 
the wheel fhould have, and that, as we have before fettled, 
fliould be two-fifths of the velocity with which the water 
moves when it llrikes the wheel. 

The wheel mufl not be placed in an open river to be ac- 
tuated by the natural current, in which cafe, after it has 
communicated Us impulfe to the float, it has room on all 
fides to efcapc : this is the fuppofititious cafe on which mofl 
mathematicians have proceeded j but in all tliele experi- 
1 1 ments, 


ments, the wheel is placed in a conduit or race, to which the 
float-boards are exaftly adapted, and the water cannot 
otherwise efcape than by moving along with the wheel. It 
is obfervable in a wheel working in this manner, that as 
loon as the water meets the float, it receives afudden check, 
and rifes up againil the float, like a wave againft a fixed ob- 
jeft, infomuch that when the fheet of water is not a quarter 
of an inch thick before it meets the float, this (heet will 
aft upon the whole furface of a float, whofe height is three 
inches ; and confequently, where the float is no higher than 
the thicknefs of the (heet of water, as theory aKo fuppofes, 
a great part of the force would have been loft by the water 
daftiing over the float. 

The wheel which Mr. Smeaton ufed had originally twenty- 
four floats, and was afterwards reduced to twelve, which 
caufed a diminution in the effeft, on account of a greater 
quantity of water efcaping between the floats and the floor 
of the channel in which it moved ; but a circular fweep 
being adapted thereto, of fucli a length, that one float en- 
tered the curve before the preceding one quitted it, the 
effeft came fo near to the former as not to give hopes of 
advancing it, by increafing the number of floats beyond 
twenty-four in this particular wheel. 

Mr. Smeaton obferves that, in many of the experiments, 
the refults were by different ratios than thofe which his 
maxims fuppofed ; but as the deviations were never very 
confiderable, the greateft; being about one-eighth of the 
quantities in queftion, and as it is not prafticable to make 
experiments of fo compound a nature with abfolute preci- 
fion, he fuppofes, that the lefTer powers are attended with 
fome friftion or work under fome difadvantages, which have 
not been duly accounted for ; and, therefore, he concludes 
that thefe maxims will hold very nearly, when applied to 
works in large. 

Application of thefe Principles to Pra&ice. — The firft thing 
to be done in a fituation where an underfliot wheel is in- 
tended to be fixed, is to confider whether the water can run 
off clear from the wheel, fo as to have no back water to im- 
pede its motion ; and whether the fall which can be obtained 
by conftrufting a proper dam to pen up the water and 
fluice for it to pafs through, will caufe it to ftrike the float- 
boards of the wheel with a fuf6cient velocity to impel them 
forcibly forwards ; and alfo, whether the quantity of the 
fupply will be fufBcient to keep a wheel at work for a cer- 
tain number of hours each day. 

When we have afcertained the height of the fall of water, 
that is, the height of the furface above the centre of the 
opening of the fluice, we muft find what will be the con- 
tinual velocity of the water iffuing out from fuch opening. 

In feme cafes, we have the velocity of the water given 
when it ifTues from the opening of the fluice, and we then 
require to know what height of column will produce that 
velocity. Thefe two things we may find by a fingle rule, 
and an eafy arithmetical operation, which is as follows : 

ifl;. The perpendicular height of the fall of water being 
given in feet and decimals of feet, the velocity that the 
water will acquire per fecond, expreffed in feet and decimals, 
may be found by the following rule : 

Multiply the conftant number 64.2882 by the given 
height, and the fquare root of the produft is the velocity 

Example I — If the height is two feet, the velocity will 
be found 11.34 feet^^r fecond. 

Example 2. — If the height is 16,0913 feet, the velocity 
will be 32,1826 iect per fecond. 

Example 3. — If the height is fifty feet, the velocity will 
be j6,68 feet/ier fecond. 

Note. The velocities thus obtained will be only the theoretic 
velocity, that is, the velocity any body would acquire by 
falling through fuch height in •vacuo, the velocity in reality 
will be lefs, generally fix or feven-tenths. 

The uniform velocity of a fluid being given, expreffed in 
feet and decimals of feet per fecond, the height of the co- 
lumn or fall to produce fuch a velocity may be found by 
the following rule ; 

Multiply the given velocity into itfelf, and divide the pro- 
duft by 64,2882 ; the quotient will be the height required, 
expreffed in feet and decimals. 

Example I. — If the velocity given is three feet per fe- 
cond, the height will be 0.139 °^ "^ foot. 

Example 2. — If the velocity given is 32,1826 feet per 
fecond, the height will be found 16,0913 feet. 

Example 3. — Let the velocity be loo feet per fecond, 
the height will be 155,649 feet. 

The knowledge of the foregoing particulars is abfolutely 
jieceffary for conftrufting an underfliot water-wheel ; but 
the moft advantageous method of fetting it to work, and to 
find out the utmoft it could perform, would be very dif- 
ficult, if we were not furnifhed with the maximum which 
Mr. Smeaton fettled, by fliewing, that an underfliot water- 
wheel will aft to the greateft advantage,' when the velocity 
of its float-boards is equal to two-fifths or four-tenth parts 
of that of the water which gives it motion. 

To illuftrate this, let us confider awheel equally balanced 
on all fides, and turning freely round upon its pivots, its 
circumference would foon move as faft as the current it 
was placed in. Suppofe the water to move at the rate of 
three feet in a fecond, the circumference of the wheel 
would pafs through three feet in a fecond. In this cafe, 
the wheel performs no work, and the effeft produced is 

Now in attempting to apply the power of this wheel to turn 
any kind of machinery, fuppofe the work to be fo proportion- 
ed, that the refiftance would caufe the wheel to ftand ftill and 
flop the water, or make it run over the floats, in confequence 
of its not having fufficient force to carry the float-boards 
along with it. In this cafe alfo, there being no motion, 
there could be no mechanical effeft produced ; but if the 
refiftance be diminiftied by degrees, the wheel would be- 
gin to partake of the motion of the current of water, and 
being loaded, would produce a mechanical effeft propor- 
tioned to the load and velocity. The wheel would increafe 
in its velocity in proportion as the refiftance was dimi- 
niftied, and the mechanical effeft would increafe alfo until a 
certain point when the wheel moved fo faft, that the water 
would not ftrike the float-boards quick enough to produce 
the greateft effeft : this is found to be as before mentioned, 
when the floats move four-tenths as faft as the water, be- 
caufe then fix-tenths of the water is employed in driving 
the wheel with a force proportional to the fquare of its 

If we multiply the furface or area of the opening by the 
height of the column, we ftiall afcertain the body or column 
of water which ftiould prefs againft that float -board, which 
is immediately under the wheel, fuppofing it has no motion ; 
but it will be found, tliat a fmall proportion of the weight 
of the original column hung on the oppofite fide of the 
wheel, would arreft its motion entirely ; but when we would 
have it to move with a proper velocity, that is, two-fifths of 
that velocity with which the water moves, t'tjV-o- of the 
weight of the original column, is the weight which the 
wheel would raife with four-tenths of the velocity that the 
water moves with, and the power which the wheel would 
exert on the machinery to grind corn, lift hammers, raife 



■water, &c. is xVrV of the weight of the water multiplied 
by T*, of '" velocity. n. a. j 

Thus it appears that an underfhot water-wheel, conftrufted 
after the foregoing manner, would only raife one-third part 
of the water expended to the fame height, as the original 
head or level. This is the utmoft that can be expefted, 
though often lefs is done ; becaufe here we fuppofe ever^- 
part exadly performed, and the water applied to the wheel 
in the belt manner ; therefore, as we cannot come up to the 
maximum, we muft come as near it as we can by lofing the 
lead poffible of the power's impulfe. 

It is no advantage to have a very great number of float- 
boards round the wheel, becaufe when they are llruck. by 
the water, as applied in the beft manner poflible, the fum ot 
the impulfes exerted on the different floats, will but be equal 
to the impulfe made againft one float-board llruck by all the 
water iffuing from the (luice at right angles to its furface. 
But as this float-board mull move forward, there mu« be a 
fucceflion of float -boards to receive the impulfe of the 
water, and lince they cannot receive it at right angles, there 
will be fome lofs of impulfe in that fucceffion. Befides 
■when the firll float-board is fo far paft the perpendicular, as 
to have the adion of the water intercepted by the fucceed- 
ing one, it is checlced by the back water through which it 
mull pafs in rifing out of the water, and thereby be fo far 
retarded as to take from the full effed of the impulfe on 
the foUowing float. Indeed if all the water could run off 
immediately after having performed its office, this would 
not happen; but it can feldom be effeded in underlhot- 
mills, efpecially thofe built upon rivers. All the remedy 
in fuch cafe is, (when the diameter of the wheel is 
fettled) to fix juft fuch a number of floats upon it. tna^ 
«ach one, after it has received the full impulfe of the 
water, may come out of the water as foon as poffible, 
that another fucceeding float may be brought to receive the 
impulfe, otherwife the wheel would remain a moment with- 
out any impulfe. 

In the article Mill we have given a table for the dimen- 
fions and proportions for underlhot wheels, which was cal- 
culated by Mr. Fergufon. Dr. Brewfter, in his new edition 
of Mr. Fergufon's works, has given an improved table, 
•which is calculated upon the following principles. 

It is evident that the water-wheel muft always move with 
lefs velocity than the water, even when there is no work to 
be performed ; for a part of the impelling power is necef- 
farily fpent in overcoming the inertia of the wheel itfelf ; 
and if the wheel has little or no velocity, it is equally mani- 
feft that it will produce a very fmall effeA. 

There is confequently a certain proportion between the 
velocity of the water and the wheel, when the effeft is a 
maximum. Mr. Smeaton has (hewn the greateft cffeA is 
produced when the velocity of the wheel is between one- 
third and one-half, but the maximum is much nearer to 
one-half than one-third. He obfcrvcs alfo that one-half 
would be the true maximum, if nothing were loft by the 
refiftance of the air, the fcattering of the water carried up 
by the wheel, and thrown off by the centrifugal force, 
and the leakages of the water between the floats and 
the water-courfe, all which tend to produce a greater 
diminution of the effed at that velocity, which would 
be the maximum if thefe lofles did not take place, than 
they do when the motion is a little flower. The great 
hydraulic machine at Marly, the wheels of which are un- 
derlhot, was found to produce a maximum clfeft when 
the velocity of the wheel was two-fifths that of the cur- 
rent. Hence Dr. Brewfter concludes that in theory the velo- 
city of the wheel is one-half that of the current, and that 

in praAice it is never more than three-eighths of the ftream'i 
velocity, when the effeft is a maximum. 

Dr. Brcujlirs Table of unJcrJbot H'ater-Wheels, in which 
the velocity of tlie wheel is three-fevenths of the velocity of 
the water, and the cffeds of fridlion on the velocity of the 
ftream are reduced to computation. The wheel is fup- 
pofcd to be fifteen feet diameter. 

Waier per Sc- 
coihI, Friflion 

Velocity of the 

Revolutions of of 

WI.eel per Se- 

the Wheel per 

ll.f F.ll of 

con<l being three- 

Minute, its Dia- 


fevcDtlis tliat of 

meter being 
fifteen Feci. 

Deinir confi'Jtrred. 

the Water. 


Feet and 

Feet and 

Revolutions and 


















































II. 31 



















! 31.42 




1 3^-33 




t 33-" 







Another Manner of applying Water to an underlhot Wbeil. 
^This was propofed by M. Fabre as the relult of much 
mathematical inveftigation, and has been fo frequently re- 
commended by authors of eminence, that we fliall give a 
(hort defcription without entering into all his rules for the 
proportions. The principal difference in this wheel from 
that in common ufe is, that the water is made to run down 
a rapid flope or inclined plane, in order to ftrike the floats 
of the wheel, inftead of iffuing from an aperture or fluice 
fituated beneath the furface of the water in the refervoir. 
A mill is ufually fituated at a diftance from the river, with 
a canal or water-courfe to condudl the water to the mill ; as 
it is of the higheft importance to have the height of the fall 
as great as poffible, the bottom of the canal or water- 
courfe, which condutfts the water from the river to the mill, 
(hould have a very fmall declivity ; for the height of the 
water-fall at the mill will diminifli in proportion as the 
declivity of the canal is increafed: it will be fufficient to 
make it flope about one inch in 200 yards, taking care to 
make the declivity about half an inch in the firft 48 yards, 
in order that the water may have a velocity fufficient to 
prevent it from flowing back into the river. 

When the water is thus brought to the channel in which 
the wheel is placed, the water is recommended to be con- 
duced down a flope or inclined plane, making an angle of 
64^ degrees with the horizon ; that is, in a perpendicular of 
ten feet, the flope (hould deviate from it 4|- feet : at the 
bottom of this flope the water is to be again conducted 
hori'/.ontally, and then to ftrike the float-boards of the 



wheel. To render the fall of the water eafy, the flope is to 
be rounded off by a convexity at top and a concavity at 
bottom, to lead the water from the horizontal to the flope, 
and again from the flope without abruptnefs. It is fup- 
pofed that the water, in running down this inclined plane, 
will acquire the fame velocity as if it had fallen perpen- 
dicularly through a height equal to the perpendicular 
height of the flope. 

The diftance through which the water runs horizontally, 
from the foot of the Hope before it afts upon the wheel, 
fliould not be lefs than two or three feet, in order that the 
different portions of the fluid may have obtained an hori- 
zontal direftion ; but if this horizontal diftance be much 
larger, the velocity of the ftream would be diminiflied by its 
friSion on the bottom and fides of the water-courfe. That 
lefs water may efcape between float-boards and the bottom 
of the courfe, it fliould be formed into the arch of a circle 
concentric with the wheel, which fweep fliould be pro- 
longed, fo as to fupport the water as long as it can aAupon 
the float-boards ; beyond this fweep fliould be a ft;ep or fall 
of not much lefs than nine inches with a flope of about 
45 degrees, that the water having fpent the greater part of 
its force in impelling the float-boards, may not accumulate 
below the wheel and retard its motion. After this ftep the 
courfe of difcharge, or tail water-courfe to run off the water 
from the wheel, fliould be floored with wood or niafonry 
about 1 6 yards long, having an inch of declivity in every 
two yards. 

The canal which condufts the water from the courfe of 
difchai-ge to join the river again, fliould flope about four 
inches in the fiift 200 yards, and three inches in the fecond 
200 yards, and fo decreafing gradually till it terminates in 
the river. But if the river to which the water is conveyed, 
fliould be fubjeft to be fwoUen by the rains, fo as to force 
the water back upon the wheel, the canal mull have a 
greater declivity, in order to prevent this from taking 
place. Hence it will be evident, that very accurate levelling 
is neceffary for the proper formation of the mill-courfe. 
The tail water-courfe ought always to have a very confi- 
derable breadth, which fliould be greater than that of the 
wheel-race, or part in which the wheel afts, that the water 
having room to fpread may have lefs depth. The feftion 
of the fluid at the point where it fl.rikes the wheel fliould be 
reftangular, the breadth of the ftream having a determinate 
relation to its depth. If there is a great ftream of water, 
the breadth fliould be triple the depth ; if there is a mode- 
rate quantity, the breadth fliould be double the depth ; and 
if there is very little water, the breadth and the depth fliould 
be equal. The depth of the water here alluded to is its 
natural depth, or that which it would have, if it did not 
meet the float-boards. The effeftive depth is generally two 
and a half times the iiatural depth, and is occafioned by the 
impulfe of the water on the float -boards, which forces it to 
fwell, and increafes its aftion upon the wheel. 

As it is of great confequence that none of the water 
fliould efcape, either below the float-boards or at their 
fides, without contributing to turn tlie wheel, the breadth of 
the float-boards fliould be wider than the flieet of water 
which ftrikes them. The diameter of the water-wheel 
fliould be as great as poflible, unlefs fome particular clrcum- 
Itances in the conftruftion prevent it ; but ought never to 
be lefs than feven times the natural depth of the ftream or 
thicknefs of the ftieet of water, where it meets the float- 
boards. The wheel will move irregularly, fometimes quick 
and fometimes flow, according to the pofition of the floats 
with refpecl to the dream ; unlefs the number of float -boards 
is confiderable, the wheel muit iiave fo many floats, that 


two floats will at leaft be always in the circular fweep at 
the bottom of the wheel; but in order to remove any 
inequality of motion in the wheel, and prevent the water 
from efcaping beneath the tips of the float -boards, it fliould 
have as many float -boards as poflible, without loading it, or 
weakening the rim on which they are placed. The float- 
boards fliould not be perpendicular to the rim, or, in other 
words, a continuation of the radius, but fliould be inclined to 
the radius ; the water wiU thus heap upon the float -boards, and 
aft not only by its impulfe, but alfo by its weight. When 
tlie velocity of the ftream is eleven feet per fecond, or above 
this, the inclination fhould never be lefs than thirty degrees ; 
or when this velocity is lefs, the inchnation fliould diminifli 
in proportion ; fo that when it is four feet, or under, the 
inclination fliould be nothing, that is, the float-boards fliould 
point to the centre of the wheel. 

It is a ftrong praftical objeftion to this manner of apply- 
ing the water to the wheel, that when the water of the river 
finks in dry weather from a deiiciency of water, it would 
not run over the top of the fall, and the mill could not work 
at all even if it funk only ten or twelve inches : in like 
manner, when the water rifes in floods, the water at the top 
of the fall would become fo deep, as to require fome Ihuttle 
to prevent it from inundating the wheels, at the fame time 
that the ftagnant water in the mill-race would prevent the 
wheel from working. Almoft all rivers are fubjeft to 
floods, and often they rife and fall, tiiree, four, fix, and 
eight feet above their ordinary level in fair weather ; now 
the water moftly rifes at the tail or difcharge of the water 
as much as the head, and the wheel-race will therefore be 
full of ftagnant water, which is called tail-water, and ob- 
ftrucls the motion of the wheel. 

In a ground-fhot wheel, where the water ifTues from a 
fliuttle on a level with the bottom of the wheel-race, it can 
always work in dry feafons, as long as the river contains 
any water, although the power diminiflies almoft to nothing, 
when the water finks low, and will not rufli out with force 
from the fliuttle. In floods of water, this wheel has a 
greater advantage, becaufe the depth of head which urges 
the flowing water is increafed when the water is high, and 
this makes it drive the tail-water forcibly out of the wheel- 
race, and enable the wheel to work, when a wheel with 
an inclined fall would infallibly be flopped. 

Breaft-wheels and overfliot-wheels, properly conftrufted, 
have ftill greater advantages, in clearing themfelves from 
tail-water, and this is a very important objeft. 

Floating-Mill tvith uiuicrjhot Wheels. — A large floating 
water-mill, to be worked by the tides or currents, was ila- 
tioned fome years ago in the river Thames, between London 
and Blackfriars bridge, by permiflion of the Board of 
Navigation. Such permiflion having been granted with the 
view of reducing, if poffible, the price of flour in the 
metropolis, and contributing to a conftant fupply of that 
neceffary article of fubfiftence. The fimplicity of this in- 
vention renders a long defcription fuperfluous, as it confilts 
in merely applying the force of two large underfhot water- 
wheels on each fide of a barge, or any other veffel calculated 
to contain the interior pan of the machinery ; the float- 
boards are difpofed in a proper manner to be afted on by 
the tide or current, fo as to give the wheels a rotatory motion, 
and by connefting therti with proper machinery, to anfwer 
thepurpofes for which the mill is intended. 

Any fliip, brig, floop, or other veffel, may be ufed for 
this purpofe, provided it is of fufficient fize to accommo- 
date the works to be erefted, yet in point of expence it will 
be better to employ fuch as are rendered unfit for fea- 

L When 


When it is intended that the ihip or mill (hould be fta- 
tionar^-, it muft be anchored, moored, or otherwifc made 
faft, fo as to fwing with the tide when necelTary ; but the 
mill may be worked while the veffel in which it is ercfted is 
failing, when wind and other circumftanccs permit. 

The number and fize of the water-wheels to be ufed may 
be varied, according to the ftze of the (hip or veflcl, or to 
the ftrength of the tide or current, and the power required ; 
and the wheels may be conftruAed as in common underfhot 
mills, or with folding-floats, for the more readily freeing 
them from the water : two wheels are to be placed verticaUy, 
on an horizontal axis, of fuch length, that, the axis being 
placed acrofs the Ihip or veflel, one wheel may run on each 
iide of it on the fame axis. 

A mill conftruAed in the manner above defcribed may 
be moved by the llrength of from two to fix large water- 
wheels, or fuch other number as the (hip or veiTel will ac- 
commodate. Thefe water-wheels may dip into the water 
from three to four, or more feet deep ; they (hould be 
fo conneded together as to be eafily engaged with and dif- 
engaged from each other, fo that during the weak part of the 
tide they may all be made to acl on one pair of mill-ftones, 
if neceffary ; and as the ftrength of the tide increafes, more 
Hones or other machinery may be put in motion, fo as at all 
times to do bufinefs in proportion thereto. 

In a mill of this kind the water-wheels do not admit of 
having water-courfes, or any equivalent contrivances, to con- 
dud the water to the wheels, as in other underfhot wheels ; 
but the float -boards muft be large enough to receive the 
power required from merely dipping into the current of the 

The vefTel of the mill in the Thames is the hull of an 
old (hip of two or three hundred tons burthen, which being 
moored in the river by chains, fo that it can fwing round 
when the tide changes, the wheels vrill always turn the 
fame way round ; one water-wheel is hxed on each fide of 
the veftel, a long iron axis being common to both ; the ex- 
treme ends of the axis are fupported in a frame work of 
timber, and another very ftrong frame of timber is fixed 
outfide of the wheels at the level of the water, which floats 
in the water, and is only attached to the mill by chains ; this 
is to protect the wheels from injury, by vefTcls which pafs and 
repafs. Each water-wheel is i8 feet diameter, and 14 feet 
broad ; the float -boards are each 3 feet deep, and are about 
fixteen in number, affixed on the circumference of cart iron- 
wheels, or circles, which are 1 2 feet diameter, there are three 
of thefe circles for each wheel ; hence we find each float- 
board expofes a furfaceof 42 fquare feet to the aftioii of the 
current, and if we fuppofe each wheel to have two floats in 
aAion at the fame time, the power of the mill will be derived 
from 168 fquare feet afted upon by the water, which fcldom 
exceeds a velocity of four miles per hour, or 352 feet per 

The iron axis of the water-wheels is a hollow tube of nine 
inches diameter outfide, and five inches within, made in four 
lengths of 1 2 feet each, properly joined together, and ex- 
tending acrofs the vcffcl from one wheel to the other. On 
the middle of this axis a large wheel of 1 1 feet diameter is 
fixed, and furrounded by a brake or gripe like that ufed in a 
wind-mill, the ufe of which is to ftop the mill when it re- 
quires repairing. Near to this brake-wheel is a large be- 
villed cog-wheel 13 feet diameter, with 89 cogs, which gives 
motion to a bevillcd pinion two feet eight inches diameter, 
with eighteen cogs fixed on the top of a vertical axis. On 
this axis is alfo a large horizontal fpur-wheel 1 2 feet dia- 
meter, with 2CI cogs, which gives motion to pinions of one 
foot diameter, and 17 cogs fixed on the fpindles of the mill- 

ftones. There are four pair of miU-ftones, two pai* of 
4^ feet and two pair of 3^ feet diameter, and the mill alfo 
works a drcffing-machine for the flour. The mill-ftones 
make 57^ revolutions for one revolution of the water-wheels, 
which move very flow, fcarcely two turns ^fr minute, in the 
moft favourable periods of the tide. The circumference of 
each taken through the middle of the float-boards is 47 feet ; 
hence the float -boards move about 94 feet per minute, when 
the mill-ftones make their proper number of revolutions to 
grind with tlie greateft eifeft. 

It was found that on a flood-tide, this mill would drive two 
pair of 3^ feet mill-ftones, and a flour dreffing-machine, but 
on the ebb-tide only one pair of 4-fect ftones and the ma- 
chine ; thus it is only the performance of a fmall mill, al- 
though the wheels are of large dimenfions, and it would 
require enormous wheels to make an effeftive floating mill 
in the river Thames. 

This machine is now removed from the river, becaufe it 
was found to do fo much injury to the velTels which continu- 
ally ran againft its floating frame, and the repairs of the da- 
mages frequently done to the mill by ice and the craft took 
away all the advantages of the mill. 

Underjbot IVhcds ■u.-ilh oblique Floats. — Attempts have 
been made to conftrucl water-wheels for tide-rivers which 
receive the impulfe obliquely, hke the fails of a common 
wind-mill. This would in many fituations be a great ad- 
vantage. A very flow but deep river could in this manner 
be made to drive mills ; and although much power would 
be loft by the obhquity of the impulfe, the remainder might 
be very great. Dr. Robinfon fpeaks of a wheel of this kind 
which was very powerful ; it was a long cylindrical frame, 
having a plate ftanding out from it about a foot broad, and 
furrounding it with a very oblique fpiral like a cork-fcrew. 
This was immerfed about one-fourth of its diameter (whicit 
was nearly 12 feet), having its axis in the direftion of the 
ftream. By the work which it was performing, it feemed 
more powerful than a common wheel which occupied the 
fame breadth of the river. Its length was not lefs than 
20 feet ; had it been twice as much it would have been nearly 
redoubled in its power without occupying more of the 
water-way. It is probable fuch a fpiral continued quite to 
the axis, and moving in a hoUow canal wholly filled by the 
ftream, might be a very advantageous way of employing a 
deep and flow current. 

In the Tranfadions of the Society of Arts, vol. xix. a 
water-wheel is defcribed, in which the float-boards are placed 
obhquely to the axis of the water-wheel at about an angle 
of 40 degrees, being fixed to the rim in pairs, which are 
inclined equally to the axis of the wheel, but in oppofite 
directions to each other ; fo that the two float-boards of 
each pair point towards each other in an angle of about 
80 degrees, and if the pair of floats were continued they 
would meet in the middle of the breadth of the wheel. The 
water is made to ftrike the floats within this angle, and in 
confequcncc all the water which is emitted by the fluice and 
ftrikes upon the oblique floats will be reflcdlcd from the fides 
or ends of the two pair of float-boards towards the vertex 
of the angle, which they make ; but the pair of floats 
do not touch each other, fo that the vertex of the angle is 
open ; but to prevent the water pafTing freely through the 
open angle, one of the float-boards is made to extend far be- 
yond the vertex, or point, where they would interfeft, and 
the other is made to fall ftiort of it, neverthelefs the water 
would certainly pafs through the opening. It is ftated, that 
the motion of the ordinary wheel with parallel floats is 
greatly retarded by the refiftance which they experience in 
rifing up or quitting the tail-water of the ftream, from the 



preflure of the atmofphere on their upper furface before the 
air gets admiffion beneath the floats ; but in Befant's wheel 
this refiftance is greatly diminiflied, as the floats emerge from 
the ftream in an oblique direftion. The water-wheel is 
conftrufted iu the form of a hollow drum, fo as to refift the 
admiffion of the water. Although this wheel is much hea- 
vier than thofe of the common conftruftion, yet it revolves 
more eafily upon its axis, as the ftream has a tendency to 
make it float. We cannot recommend this wheel, but on 
the contrary think it one of the worft forms, as it tends to 
increafe that lofs which arifes in all underfliot-wheels from 
the change of figure which the water muft undergo when it 
ftrikes the float, and we rtiould not have mentioned it, but 
that it has been fo frequently copied and recommended by 
different authors. 

Hor'ir.onlal Water- wheeh aBuated by the Impulfe of Water. 
— Thefe have been confiderably in ufe on the continent, and 
deferve our notice from the fimplicity of their conilruftion. 
The wheel is conftrufted in the fame manner as an under- 
fhot-wheel, having float -boards fixed round its circumference 
in the form of radii ; it is mounted on a vertical axis, the 
upper end of which is fixed to the fpindle of the mill-ftone, 
if the mill is intended to grind corn ; but in fome cafes, it is 
better to fix a cog-wheel on the upper part of the vertical 
axis with teeth round its edge, to give motion to trundles 
or pinions on the fpindles of the mill-ftones, becaufe the 
floats of the wheel mufl; always be made to move with a 
given proportion of the velocity of the water. The wheel- 
race or water-courfe may be made nearly the fame as for an 
underfliot-wheel, if we fuppofe it laid down in an horizontal 
pofition ; that is, a trough or channel of mafonry is con- 
ftrufted in wliich the wheel works, and the float-boards of 
the wheel are exaftly fitted to it : at one end of this chan- 
nel is the aperture or fluice through which the ftream of 
water ifl^ues, and ftrikes the floats of the wheel fo as to 
turn it round, and the water pafles forwards and efcapes at the 
other end of the channel. When the water is delivered upon 
the wheel in an horizontal direftion, or perpendicular to its 
axis, the float-boards ftiould be inclined about twenty-five 
degrees to the plane of the wheel, and the fame number of 
degrees to the radius, fo that the loweft and outermoft fides 
of the float-boards may be fartheft up the ftream and be met 
by the water firft. 

In many cafes, the water-courfe is made inclined to the 
plane of the wheel in fuch a degree, that the water may ftrike 
the float-boards perpendicular to their furfaces. 

In the fouthern provinces of France, where horizontal 
water-wheels are generally employed, the float-boards are 
made of a curvilineal form fo as to be concave towards the 
ftream ; they are generally fegments of fpheres, or hollow 
wooden bowls or ladles fixed on the rim of the wheel : the 
water, in this cafe, is condufted through a pipe, and pro- 
jefted in a jet on a direftion a little inclined to the horizon. 
When the height of water is very confiderable, this is, 
perhaps, the beft form for the floats, or ladles, as they are 

The chevalier de Borda obferves, that in theory a double 
effeft is produced when the float-boards are concave, but that 
the effeft is diminifhed in praftice, from the difficulty of making 
the fluid enter, and leave the curve in a proper direftion. 
Notwithftanding this difficulty, however, and other defefts 
which might be pointed out, horizontal wheels with con- 
cave float-boards are always fuperior to thofe in which the 
float-boards have plane furfaces. 

Mr. Smeaton conftrufted a fmall corn-mill with a hori- 
zontal water-wheel, of which the following are the prin- 
cipal dimeofions. Fall of water 52^ feet; diameter, or 

bore of the nofe-pipe through which the water ifTued in 
a jet to ftrike upon the wheel, i\ inch ; diameter of the 
water-wheel 10 feet to the centre of the floats or ladles, 
which were twelve in number ; they were made of a concave 
form, nearly fegments of fpheres, and about 14 inches in 
diameter ; and fixed round the circumference of the wheel, 
fo that the planes of the circular rims, or edges of the 
hollow ladles, were not perpendicular to the plane of the 
wheel, but inclined thereto in fuch a degree, that the jet of 
water ifluing from the nofe-pipe at an angle of 22 degrees 
from the horizontal line, would ftrike the floats in the centre 
and perpendicular to the circular edge of the hollow ; the 
internal furface of the floats being really fpherical, the water 
would always ftrike perpendicularly into the concavity of 
the bowl. The water-wheel axis rofe up perpendicularly 
into the mill-houfe, and on the top a wheel of 4 feet 8 inches 
in diameter, and 44 cogs, was fixed for giving motion to the 
pinions on the axis of the mill-ftones. The largeft pinion 
of 1 7 cogs was fixed on the axis of a pair of ftones 4 feet 
6 inches in diameter, and the fmaller pinion of 1 3 cogs on 
the axis of a ftone 3 feet 6 inches in diameter. It wa« 
not intended to turn both thefe pairs of ftones at the fame 
time, but it was neceffary to have two pairs for different 

When this mill moved with a proper velocity to grind 
to the greateft advantage, if the 4 feet 6 inches ftones were 
ufed, the water-wheel made 25 revolutions per minute, and 
the ftones therefore made 65 revolutions per minute, and 
the float -boards moved with a velocity of 784 feet per mi- 
nute ; but when turning the fmaller mill-ftones of 3 feet 
6 inches diameter, the water-wheel went beft when it made 
26 revolutions, and therefore turned the mill-ftone 88 turns 
per minute ; and the velocity of the floats was 816 feet per 

Mr. Smeaton calculated the velocity of the water ifTuing 
from the pipe at 3403 feet per minute, which is the velocity due 
to a 50 feet feet, becaufe he allowed the 2| feet to overcome 
friftion, and the expenditure of the l| inch nofe-pipe at 30 
cubic (eetper minute allowing for friftion. This mill ground 
one bufhel of wheat per hour, on the average of a great 
many experiments, now 30 X 50 = 1500 cubic feet, falling 
one foot per minute. It is found by repeated experiments, 
that 600 cubic feet faUing one foot per minute on a good 
water-wheel is an ample allowance for grinding a buftiel of 
wheat, as it may be done by 530; hence this fall of water 
ought to have ground 2^ bufhels per hour inftead of one. 
The mill, however, admits of improvement in making the 
floats of the wheel move quicker. 

When the mill-ftone of an horizontal mill is fixed on the 
upper end of the axis of the water-wheel, if the mill-ftone be 
five feet in diameter, it (hould never make lefs than fixty tutus 
in a minute, and the wheel muft perform the fame number 
of revolutions in the fame time ; and in order that the 
effeft may be a maximum, or the greateft poflible, the ve- 
locity of the current muft be more than double that of tlie 

Suppofe the mill-ftone, for example, to be j feet dia- 
meter, and the water-wheel 7 feet, it is evident that the 
mill-ftone and wheel muft at leaft revolve 60 times in a mi- 
nute ; and fince the circumference of the wheel is 22 feet, 
the float-boards will move through that fpace in the 60th 
part of a minute, that is, at the rate of 22 feet per fecond ; 
which being doubled, makes the velocity of the water 
44 feet one fecond, anfwering, as appears from the rule, 
for the velocity of falling water, to a fall of 30 feet. But 
if the given fall of water be lefs than 30 feet, we may 
procure the fame velocity to the mill-ftone, by diminifh- 
L 2 ing 


inff the diameter of the wheel. If the wheel, for inftance, friaion, or refiftance, which the water would find in fuclr 

■g only 6 feet diameter, its circumference will be 18.8 circulation, caufes the wheel to turn round with the water, 

feet lad its floats will move at the rate of 18.8 feet in unlcfs the load on the wheel, or refittance to its motion, i* 

a fecond, the double of which is 37.6 feet per fecond, too great. . „ , 

which anfwcr'i to a head of water 22 feet high. The dia- The water which n continually thrown into the wheel 

meter of the water-wheel, however, Should never be lefs than cfcapcs from the annular fpace by paifagcs which proceed 

6 or 7 feet bccaufe the float -boards change their diredion from the bottom thereof to the centre of the wheel ; ancf 

fo raoidlv 'in confequcnce of their proximity to the centre, there .ire openings at the centre, where the water can drop 

that they will not receive the full aftion of the water, be- out Mo':i: To form the parages for this purpofe, the folid 

caufe it ads in a perpendicular diredion to the float -board cylinder which is fixed in the centre of the hollow drum is 

only for a moment. Hence there will be a certain height of lefs depth than the other, and leaves a fpace between the> 

of the fall beneath which the fimple horizontal wheel can- bottom of the folid and the bottom of the hollow, which 

not be em'ployed • and beyond that, wheel-work mull be is divided into compartments by diaphragms fixed upon thr 

introduced to obtain the requifite velocity for the mill- bottom of the trough, and proceeding like radii from the 

„ circumference to a central hole in the bottom- of the trough, 

"irihe provinces of Guienne and Languedoc, in France, which is left open to allow the water to elcape. The report 

another fpecies of horizontal wheel is employed for turning fl.ites, that the velocity with which the water ifl"ues from 

machinery It confifts of an inverted cone, with fpiral the jets makes the machine move round its axis ; and this 

float boards of a curvilineal form winding round its furfacc. motion accelerates by degrees, till the velocity of the water 

The'wheel moves on a vertical axis in a pit or well of ma- in the annular fpace equals that of the water from the re- 

ionrv to which it is exadly fitted, like a coffee-mill in its fcrvoir, fo that no fenfible fhock is perceived of the affluent 

box ' It is driven chiefly by the impulfe of the water, con- water upon that which is contained in the machine. The 

veve'd by a fpout or canal in a ftream, which Ilrikes the ob- motion of the wh.eel is regular, becaufe the aftion is con- 

liaue float-boards • and when the water has fpent its impul- tinual ; but in the cafe of other water-wheels, where the 

five force it defce'nds along the fpiral float -bo.irds, and con- water ilrikes againll float-boards, iuch boards muft necef- 

tinues to 'ad by its weight till it reaches the bottom, where farily be of a determinate number, and the motion muft be 

it is carried off by a canal. The idea of this machine is in- given to the wheel by a fucceffion of impulfea, as the floats 

p-enious The jet of water, being firll applied to the upper arrive before the ftream. We might indeed iuppofe a wheel' 

8r larec'll part of the cone, ftrikes the float-boards at the with an infinite number of floats, but it would then amount 

nart where they move with the greateft velocity, in confe- to a plain cylindrical or flat lurface, upon which the water 

quence of their being on the largeft radius ; but as the water would not take fufficient hold to produce any fenfible effort 

lofes its velocity, in confequence of the motion it has im- to turn it round. , - , 

DWted to the wheel, it defcends in the cone, and afts upon Now in M. Dedot's wheel, in place of float-boards, the 

the floats lower down, where, the radius being lefs, the rim of the wheel is clothed with water, whicli is capable of 

floats move more flowly, and are therefore better adapted being aded upon by the water iffuing from the jets. Tliis 

to receive the a6lion of the water with its diminiflied ve- adioii tends to put the water in the annular fpace in motion, 

, - and to carry the wheel along with it, by the adhefion it 

°^M Mannoun Depot's horizontal Walcr-lVhcel, -which muft naturally have to the fides of tlie channel which con- 

hc calls Danaij/— This receives the impulfe of the water in tains it. Tlie velocity of the wheel will be 111 proportion to 

different manner from any which we have defcribed, and the refiftance that the load makes to its motion, 

defcribed in a report to the Inftitute of France in 1813. The circular motion of the wheel communic 

is defcribed in a report 

circular plane, which forms the bottom. Within this drum, proaches the centre, 
and concentric with it, a folid cylinder is fixed ; it is of lefs The whole mais of 
dimenfions than the drum itfelf, and occupies fuch portion pofite forces, viz. gra 

communicates a centri- 
The watVrwiieel is fixed in a horizontal pofition upon a fugal force to the water contained in the annular cavity of 
vertical axis and fupportcd upon the pivots thereof, fo as its rim, which caufes u to prefs againft the outermoft fide 
to be capable of turning round. It is not in reality a wheel, of the channel. This centrifugal force ads equally upon 
but a hoUow cyhnder or drum capable of containing water ; the water contained in the compartments at the bottom of 
it is open at top, and united to the axis in the centre of the the faid rim ; but its adiou dimmilhes as the water ap- 
- -„.,„ ,„v,;^l. f„,m«tl,oKnttnm. Within this drum, proaches the centre. 

water is then animated by two op- 
gravity and the centrifugal force. The 
of X'MnVnt'of'thc^drum as to reduce the open part' wliich firft tends to make the water run out at the hole in the hot- 
can contain water to a hollow ring or circular trough, open tom of the wheel at the centre, and the fecond to drive the 
at top, and of a confiderablc depth, but only a few inches water from that hole. 

in width. The depth is defcribed as being nearly as great To thefe two aftions ar? joined a third, wz. fridion or 
as the diameter of the wheel. 

The water coming from an elevated refervoir, is pro- . 

iefted in icts from one or more pipes into this annular fpace of adion, while in moft other machines it always diminifhes 
which furrounds the rim of the wheel. Thefe pipes defceiid their powers. The effed in this machine would be nothing 
clined dircdion, till they are nearly on a level with were it not for the refiftance which the water finds oppofed 

' ' to its free circulation in the annular fpace round ttie rim of 

the wheel. 

By the combination of thefe three forces There ought to 
refult a more or lefs rapid flow of water from the hole in the 

refiftance, which ads an important and fingular part ; and 
in this machine the fridion of the water produces its powers 

m an inc , , . 

the furface of the water in the annular fpace ; and the ex- 
tremities turn horizontally, fo as to projed the jet horizon- 
tally, and in the dircdion of tangents to the mean circum- 
ference of the water contained in the annular fpace. 

Suppofe this fpace which furrounds the wheel is full of centre at the bottom of the wheel ; and the flower this water 
Iter then the ftream iffuing from the jet caufes the wheel iffues, the greater will be the efledive power of the machine 
tur'n round upon its axis,' bccaufe it takes hold or ads for producing tlie ufetul effed for which it is deftincd. 


to turn round upc 

upon the water in the annular fpace, and tends to give tlie r , " - ,-, • , ., , , ,,- ,• j 

water a circulating motion within the annular fpace ; but the weight of the water wluch runs luto the wheel, multiplied 

4 ^y 

The moving power in tliis machine, like all otiiers, is the 


hy the elevation the refervoir has above the bottom of the 
wheel, or orifice from which it iffues in quitting the fame ; 
but the iifeful mechanical effeft is ftated to be equal to that 
produft, diminifhed by half the force which the water re- 
tains, when it flows out at the orifice below, and quits the 

In order to afcertain, by direA experiment, the magni- 
tude of this effect, Mcflrs. Prony and Carnot fixed a cord 
to the axis of the machine, which paffing over a pulley, 
raifed a weight by the motion of the machine. By this 
means the effed. was found to be -rVths of the power, and 
often approached -,Voths, without reckoning the friftion of 
the pulleys, which has nothing to do with the eil'eft. 

We cannot help fufpefting fomc miftake in thefe experi- 
ments, or in the ftatement of them, but think the machine 
deferves a trial ; and if it Ihould produce near the refult 
above flated, it would be a moft valuable addition to our 
means of employing falls of water ; and its fimplicity would 
be a great recommendation, particularly for corn-mills, be- 
caufe the perpendicular axis is immediately adapted for that 
purpofe, without any wheel-work. 

Horizontal Mill luith oblique Vanes In Belidor's Archi- 

tefture Hydraulique he defcribes a different form of hori- 
zontal mill. The v»rheel is a circular rim, and tlie radii or 
arms are all oblique vanes or floats, precifely the fame as the 
common fmoke-jack. This wheel is placed horizontally in 
a well, to which it is exaftly fitted, but the rim of the wheel 
does not touch the circular wall of the well. The axis of the 
wheel afcends upwards into the nilll-houfe, and the fpindle 
of the mill-ftone is fixed into it. A horizontal arch-way is 
condufted to the well fideways, and above the part where the 
wheel is fitiiatcd. This arch conveys the water into the 
well over the wheel ; and beneath the wheel there is a fimilar 
horizontal arch to carry away the water, after it has pafl'ed 
tlirough the wheel, that is, in the fpaces between its vanes 
or floats. The weight of the water prefTes upon them in a 
perpendicular direAion, and the planes of thcfe floats being 
all inclined to the horizon, the aftion of the prefFure tends 
to turn the wheel round on its axis, by the fame aftion as 
the fmoke upon the vanes of a jack, or like a wind-mill. 

The water is fupplied in fuch a body through the upper 
arch, that the well is always kept full, with a confiderablc 
depth of water prefTuig upon the wheel ; whilfl the lower 
arch carries away the water fo freely, that it runs away 
from beneath the wheel as fall as it can pafs through the 
vanes of the fame. 

The mill defcribed by Belidor was at Touloufe, and 
contained a number of fuch wheels in a row, each giving 
motion to one pair of Hones. 

Horizoiilal Machines moved by the Readion of Water. — 
The reaction of water, ifTuing horizontally through a fpout 
or orifice, may be employed to communicate motion to 
machinery ; and though this principle has not yet been 
adopted in pra£lice, it appears from theory, and from fome 
detached experiments on a fmall fcale, that a given quantity 
of water, falling through a given height, will produce greater 
effefts by its reaftion than by its impulfe. If we fuppofe 
a vertical pipe of any given height, open at both ends, and 
that water is poured into it at the top, the water will ifTue 
at the bottom of the pipe with a velocity proportioned in a 
certain manner to its altitude, becaufe every particle of water 
which iffues is prefTed upon and impelled by the weight of 
all the particles which are above it. Now, fuppofe the 
pipe bent or curved at the bottom, fo that it will turn the 
llream of water into a horizontal pofition ; in this cafe, the 
prefFure and force, of which we have fpoken, wOl be de- 
flcded from the vertical direftion to the horizontal. Now 

it is clear that the bent part of the pipe, or fome part of the 
interior furface of the tube oppofite to the orifice, mufl fuf- 
tain all the prefFure which is thus deflofted or tranfmitted in 
another direfkion ; and if the tube is freely fufpenilf d, it will 
retreat before this prefFure, and be put in miction. If we 
fuppofe the tube to have no refi fiance to motion, then it 
would receive all the motion of the water, which would not 
move at all after it ifFued from the orifice, but the orifice 
and tube would move away from the water. This is an im- 
poffible cafe, and in reality the motion of the effluent water 
will be divided between the pipe or tube and the ifFuing 
water, in proportion to the refiflance with which each is 
loaded. Another and perhaps more famihar explanation is, 
that the water prefFes againft: every part of the interior part 
of the pipe, except againft. the orifice or aperture, which is 
open ; and in confequence, the unbalanced prefFure on the 
part oppofite to the orifice will tend to put the pipe in 
motion. A flcy-rocket mounts in the air from a fimilar caufe. 
Dr. Barker's mill by the reaftion of luater was the firft of 
this kind of machines, and is defcribed by Defaguliers, in 
1743. In his Experimental Philofophy, vol. ii. p. 460, he 
calls it a machine to prove Mr. Parent's propofition experi- 
mentally, vix. that an under-fhot water-mill does moft work, 
when the water-wheel moves with only a third part of the 
natural velocity of the water that drives it. He fays, that 
Dr. Barker had this thought, and communicated it to him, 
faying, that it would be an experimental proof of Mr. Pa- 
rent's propofition ; in confequence of which, Defaguliers 
made a working model of it, which he fhewed to the Royal 
Society, and the experiments upon it, at their meeting in 

It confifls of an upright pipe or trunk, communicating 
with two horizontal branches, hke an inverted T ; thus, j^. 
This perpendicular pipe is poifed upon a pivot at the lower 
end, and the upper end is connefted with the fpindle of the 
mill-tlone, or other machine to which it is to communicate 
motion. The top of the pipe is formed into a funnel, into 
which a ftream of water is condufted, and runs down the 
pipe : the water efcapes through a hole in each of the 
horizontal arms, which holes are near the ends of the arms, 
and open in oppofite diredtions, and in fuch a pofition that 
they will direft the ftream of water horizontally, and nearly 
at right angles to the length of the arms. 

Suppofe water to be poured in at the top of the tube 
from the fpout, it will then run out by the holes at the ends 
of the arms, with a velocity correfponding with the depth 
of thefe holes beneath the furface of the water in the vertical 
pipe. The confequence of this mufl be, that the arms 
mufl be prefTed backwards, for there is no folid furface at 
the hole on which the lateral prefFure of the water can be 
exerted, while it a£ls with its full force on the infide of the 
tube oppofite to the hole. This unbalanced prefFure, afting 
upon the oppofite fides of both arms, will make the tube 
and the horizontal arm revolve upon the fpindle as an axis. 

This will be more eafily underftood, if we fuppofe the 
onfices to be fhut up, and confider the prefFure upon a cir- 
cular inch of the arm oppofite to the orifice, the orifice 
being of the fame fize. 

The prefFure upon this circular inch will be equal to a 
cylinder of water, whofe bafe is one inch in diameter, and 
whofe altitude is the height of the fall ; and the fame force 
is exerted upon the tliut-up orifice. Thefe two prefFures 
being equal, and a£ling in oppofite direAions, the arm will 
remain at reft ; but as foou as the orifice is opened, the 
water will ifFue with a velocity due to the height of the fall. 
The prefFure of the water upon the orifice will now be re- 
moved, and as the prefFure upon the circular inch oppofite 



to the orifice ftill contiiiufs, the equilibrium will be de- 
ftroyed, and the arm will move in a retrograde direftion, 
unlefs it is withheld by fome force greater than that pref- 

In the original model made by Defaguliers, the vertical 
tube was a cylindrical pipe, but the lower arms were of a 
fquare figure in their crofs feftion, and the apertures 
through which the water iffued were likcwife of a reftan- 
gular figure, and provided with (liders or fluices, which 
were regulated by fcrews fo as to increafe or diminifh the 

It is clear that the machine mufl prcfs backwards, and 
there is no difficulty in underftanding the intenfity of this 
preffure, when the machine is at relt. But when it is al- 
lowed to run backwards, withdrawing itfelf from the pref- 
fure, the intenfity of it is diminifhed ; and if no other cir- 
cumftances intervened, it might not be difficult to fay what 
particular prelTure correfpoiided to any rate of motion. 
Defaguliers affirms the preffure to be the weight of a co- 
lumn, which would produce a velocity of efflux equal to 
the difference of the velocity of the fluid and of the machine : 
and hence he deduces, that its performance will be the 
greateft poffible, when its retrograde velocity is one-third of 
the velocity acquired by falling from the furface ; in which 
cafe, it will raife ^^ths of the water expended to the fame 

But this is not a pcrfcft account of the operation ; for 
the water which ifTues defcends in the vertical trunk, and 
then moving along the horizontal arms, partakes of their 
circular motion. This excites a centrifugal force, which 
muft be exerted againft the ends of the arms by the inter- 
vention of the fluid. The whole fluid contained in the arras 
is fubjeft to this aftion, each part in a degree proportioned 
to its diftance from the axis, becaufe every particle is prefled 
with the accumulated centrifugal forces of all the feftions 
that are nearer to the axis. This increafes the velocity of 
revolution, and this mutual co-operation would feem to lead 
to a continual acceleration in the velocity of both motions. 
But, on the other hand, this circular motion muft be given 
anew to every particle of water, when it enters the Hori- 
zontal arm. This can be done only by the motion already 
in the arm, and at its expence ; neither can the perpendicular 
tube furnifli an unlimited fupply. Thus there muft be a 
velocity which cannot be exceeded even by an unloaded 

Improved Form of Dr. Barter's Mil! — This confifts in 
introducing the fupply of water at the lower end of the 
tube, inftead of the upper end. It was firft propofed by 
M. Mathon de la Cour, in the Journal de Phyfique, 1775 ; 
and the invention was, 20 years afterwards, claimed by a 
Mr. Ranifey, and very recently by M. Mannoury DeAot 
in France. This laft machine is very highly recommended 
by Men"rs. Perier, Prony, and Carnot, in a report to the 
Inftitute, from which we make the following extrafts. 

The water is introduced into the revolving arms at the 
lower part, through the axle : the pipe which brings the 
water cnclofes the pivot, upon which it turns. This water 
is brought to the rcfervoir through a curved canal, by means 
of which the revolving arms, and the mill which it puts in 
motion, are placed by the fide of the refervoir, and neither 
above nor below it, which would much injure the working, 
and the fimplicity of the machine. By bringing the water 
from below, by means of a canal, the machine is reduced to 
a fimple water-wheel, the axis of which is fixed immediately 
to the moving mill-ftone. 

Although the water enters with little velocity into the 
revolving arms, it caufes them to turn very faft, becaufe 

the apertures for its egrefs being much fmaller than thofe 
for its entrance, the velocity at the entrance is reciprocally 
much fmaller than it is at the egrefs. But this velocity at 
the egrefs is not an abfolute motion ; it is only a relative 
motion with refpeiEl to the tube from which it in"ue3, other- 
wife there would refult a fpontaneous augmentation of 
power, which would not agree with the principles of me- 

The apertures for the entrance and the egrefs of the water 
being proportioned as they ought to be, in order to obtain 
the greateft effect ; then the report ftates, 

1. The reaftion, that is, the force of prclTure which afts 
upon the revolving arms, at each of the apertures of egrefs, 
is equal to the weight of a column of water of the fame 
bafe as the aperture, and of the height of the level of water 
in the refervoir. 

2. The velocity of the rotation of the arms meafured at 
the fame points is to the velocity due to the height of the 
level of the water in the refervoir, as the aperture for the 
entrance of the water into the mill-wheel is to the funi of the 
apertures of egrefs. 

Whence it follows, by multiplying this force and this 
velocity, that the effeft produced by the machine in a given 
time is equal to the weight of all the water that the rcfervoir 
can furnifh during this time, by the height of the level of 
the water in the refervoir. Now this produft, it is well 
knovm, is the utmoft that can be obtained by the beft hy- 
drauhc machines. 

This difpofition of Dr. Barker's machine has a confider- 
able advantage, which is, that the column of water which 
enters into the arms, by preffing from below on the part 
above, with all the weight of the refervoir, fuftains a great 
part of the weight of the machine, and confequently greatly 
diminifhes the friftion of the pivot againft the focket in 
which it turns ; while, on the contrary, when the water 
enters at the top, as in the old reafting machines, which is 
already very heavy of itfelf, this flowing water "fconfiderably 
augments the weight, and confequently the refiftance. 

This difpofition cannot be ufed, except where the bulk of 
water is not very confiderable. 

As the arms turn, while the conduit which brings the 
water is immoveable, the pipe that brings the water to enter 
the collar of the arms is rather lefs than the collar, fo as to 
leave very little play between them, and is made tight by 
furnifhing this fmall interval with a leather collar. Another 
method is by furnifhing the tube at bottom, which is fixed, 
and the moveable collar of the wheel, with feveral cyUndrical 
and concentrical furfaces, which fit one into the other with- 
out touching. The water fills the deep and clofe grooves 
formed by the cylindrical furfaces, and is fufficient to pre- 
vent that which is forced into the wheel from efcaping by 
the fides. 

Dr. Robinfon defcribes a fuperior method of making fuch 
a joint, as will admit of a free motion, without any lofs or 
leakage. This is to make the fixed and moveable tubes 
very true at the joints, fo that one enters into the other, but 
do not touch. The two tubes are to be made exaAly of 
the fame diameter withinfide at the joint, fo that a band of 
thin leather can be applied withinfide of the joint, to cover 
the crevice : this muft be fixed to the interior of the fta- 
tionary tube, and the revolving part being fmooth within- 
fide, will have very little friAion, as it is only rubbed by 
the leather ; but there can be no leakage at the joint, be- 
caufe the water will prefs the leather clofe to the moving 
tube, but as mucli water will get in between the leather ana 
the moving tube as to make it move fmoothly. 

Theory of Barier't Mill. — This is a mofl delicate fubjeft, 



add upon which it does not appear that fufficient experi- 
mentshave been made to found a certain theory. 

Mr. Waring, of the American Philofophical Society, has 
given a theory of Barker's mill with the laft-mentioned im- 
provement, and, contrary to every other philofopher, he 
makes the effeft of the machine equal only to that of a 
good underftiot wheel, moved with the fame quantity of 
water falhng through the fame height. 

Mr. Gregory, in his Mechanics, vol. ii. haa given this 
paper with fome correftions, and recommends it as the bed 
theory. The following rules, deduced from his calculus, 
may be of ufe to thofe who may wifh to make experiments 
on the effc6> of this interefting machine. 

1. Make each arm of the horizontal rotatory tube or 
arm of any convenient length, from the centre of motion to 
the centre of the apertures, but not lefs than one-third (one- 
ninth according to Mr. Gregory) of the perpendicular 
height of the water's furface above their centres. 

2. Multiply the length of the arm in feet by .6136, and 
take the fquare root of the produdl for the proper time of 
a revolution in feconds, and adapt the other parts of the 
machinery to this velocity ; or if the required time of a re- 
volution be given, multiply the fquare of this time by 1.629 
for the proportional length of the arm in feet. 

3. Multiply together the breadth, depth, and velocity /icr 
fecond, of the race, and divide the laft produft by 18.47 
times ( 14.27 according to Mr. Gregory) the fquare root of 
the height, for the area of either aperture. 

4. Multiply the area of either aperture by the height of 
the fall of water, and the produft by 41' pounds (55.775 
according to Mr. Gregory) for the moving force, ellimated 
at the centres of the apertures in pounds avoirdupois. 

5. The power and velocity at the aperture may be eafily 
reduced to any part of the machinery by the fimpleft me- 
chanical rules. 

The only account we have of an aftual machine, except 
the firft model by Dcfaguliers, is by M. Mathon de la Cour, 
who faw one at Bourg Argental, of the following dinien- 
fions. Length of the revolving arms feven feet eight inches, 
and diameter three inches ; diameter of each orifice i^ inch ; 
fall of water, from the level furface in the refervoir to the 
apertures in the revolving arms, twenty -one feet. The water 
was introduced at the lower end of the revolving axis, 
through an opening of two inches, the two furfaces being 
fitted together by grinding. 

When this machine was performing no work, and emitted 
water by one hole only, it made 115 turns per minute. 
This gives a velocity of (24 feet circumference x 115 =) 
2760 feet per minute for the hole ; but the effluent velocity 
by theory would be only 2215 feet per minute at 2 I feet 
height, and in reality would be little more than fix-tenths of 
that velocity, or about 1370 feet per minute. Dr. Robin- 
fon fuppofes even this to be much lefs than the velocity with 
which the water iffued from the pipe, as we may readily be- 
lieve, becaufe all the force of the machine was expended in 
working hke a centrifugal pump, to draw the water out of 
the pipe of fupply, with a velocity greater than that with 
which it would run by the preffure of the column alone. 
The empty machine weighed 80 pounds, 28-5 pounds of 
which would be borne up by the preiTure of the column of 
2 1 feet on a two-inch bafe, fo that the fridlion of the pivot 
would be much diminiihed. We have no account of any 
work done by the machine, as it was only employed to turn 
a ventilator for a large hall. 

Euler's Machine to ad by the ReaSion of Water. — His ma- 
chine confifts of a hollow conchoidal ring, that is, a folid 
fhaped juft like a large church bell. Suppofe alfo another 

bell, of fmaller dimenfions, placed within the former, and 
leaving a fpace all round between the two, the two bell* 
are joined at the lower edges, fo that the water cannot 
efcape from the fpace between them. This machine is 
mounted on a perpendicular axis, and on the top is a fort of 
funnel bafon, which receives the water from the fpout, not 
in the direftion pointing towards the axis, but in the direc- 
tion of a tangent, and the water is delivered with the pre- 
cife velocity of the wheel's motion. This prevents any re- 
tardation by dragging forward the water. The water partes 
down from the funnel or bafon between the outer conchoid 
or bell, and the inner conchoid, through fpiral channels 
formed by partitions foldered to both conchoids. The 
curves of thefe channels are determined by a theory which 
aims at the annihilation of all unneceflary and improper motions 
of the water, but which is too abllrufe to find a place here. 
The water thus condufted arrives at the bottom of the 
fpace between the two bells. On the lower circumference 
of this bottom is arranged a number of fpouts, one from 
each fpiral channel, which are all direfted horizontally, and 
turned one way in tangents to the circumference. 

The fame effefts will be produced, if we fuppofe only 
one bell, with a number of tubes or pipes wound in a fpiral 
direftion round its external circumference, the lower ends 
of each tube being turned horizontally, and in the direction 
of tangents to the circle which it defcribes, alfo the upper 
or higher extremities of the tubes, connefted with a circu- 
lar fuperficies into which the water flows from a refervoir. 
When the machine has this form, it has been (hewn by Al- 
bert that the effeft will increafe as the velocity is augmented, 
and that the maximum effeA would be produced if the ve- 
locity could be infinite, and that then the effeft would be 
equal to the power. A confiderable portion of the power 
muft, however, be confumed, in communicating to the fluid 
the circular motion of the tubes ; and, as the portion thus 
lofl; mufl: increafe with the velocity of the tubes, the effeft 
will not in reahty fuftain an augmentation from an increafe 
of velocity, beyond a certain point. 

It is plain that this form of the machine muft. be a moft 
cumbrous mafs ; even in a fmall fize and height it would 
require a prodigious veffel, and mufl carry an unwieldy load. 
If we examine the theory which recqmmends this conftruc- 
tion, we find that the advantages, though real and fenfible, 
bear but a fmall proportion to the whole performance of the 
fimple machine, as invented by Dr. Barker. It is therefore 
to be regretted, tiiat engineers have not attempted to realize 
the firfl: projeft. 

Machines aauated by the Weight of Water. — The principal 
of thefe are breaft-wheels, overlhot-wheels, chains of buckets, 
and prefl"ure-enginc3. All thefe have an eflential difference 
j^ora the machines which we have yet defcribed, becaufe the 
water is prevented from defcending, unlefs the machine 
moves before the water. This is not the cafe with the ma- 
chines which receive their motion from the impulfe of the 
water, becaufe the water is fuffered to defcend and acquire 
its full velocity before it ftrikes the machine. 

In reafoning without experiment, we might be led to 
imagine, that, however different thefe modes of application 
are, yet whenever the fame quantity of water defcends 
through the fame perpendicular fpace, the effeftive powers 
of two machines, which are aftuated by fuch fall of water, 
would be equal, provided that the machines were free from 
friftion, and equally well calculated to receive the full effedt 
of the power of water, and to make the moft of it. 

For if we fuppofe the height of a column of water to be 
thirty inches, and that it refts upon a bafe or aperture of 
one inch fquare, then every cubic inch of water that departs 



from the lower end of Uie column will acquire the fame 
velocity of motion, from the uniform prefTure of the thirtv 
cubic inches which arc above it, that one cubic inch let fall 
from the top would acquire in falling down to the level of 
the aperture^ r/«. fuch a velocity as in a contrary direftion 
would throw or projeft it to the level from whence it fell, . 
the weights and velocities in both thefe cafes being equal, the 
produ<?ks, or what we have called mechanical powers, will 
alfo be equal. We might therefore be led to fuppofe, that 
a cubic inch of water, let fall through a fpace of thirty 
inches, fo as to inpinge upon a folid body, would be capa- 
ble of communicating thereto an equal motion or mechanical 
effeft by colhfion, as if the fame cubic inch had defcended 
through the fame fpace with a flower motion, and produced 
the effeA gradually ; for in both cafes gravity acls upon an 
equal quantity of matter through an equal fpace. 

It is true that the gravitating force afts a longer fpace of 
time upon the body that defcends flowly, than upon the 
other which falls quickly ; but this cannot occafion the dif- 
ference in the effeft : for we find by experiment, that an 
elaftic body falling through any given fpace will, by coUifion 
upon another elaftic body which is fixed, rebound nearly to 
the height from which it fell : or, by communicating its 
motion to a body equal to itfelf, will caufe that body to 
afeend to the fame height. On thefe principles we might 
conclude, as fome authors have done, that whatever was the 
ratio between the power and effeft in underfhot wheels, the 
fame would hold true in overfhot, and indeed in all others. 
However conclufive this reafoning may feem, it will ap- 
pear, in the courfe of the following deduftions, that the 
effeft of the gravity of defcending bodies is very different 
from the effeft of the flroke, of fuch as are mn-elajlu, 
though generated by an equal mechanical power. 

It is true that, in the cafes we have above fuppofed, the 
power of the fall of water is the fame ; but the problem 
propofed to the engineer is, to obtain from it all or as 
much as pofTible of the power, and render it applicable to 
fome ufeful purpofe. We have already given our definition 
of power, that it is weight or matter compounded with 
motion. Now to obtain all the power from any flream of 
water, we muft abftraft from it all its weight and all its 
motion. In underfhot wheels, or any others moved by the 
impulfe of the water, we cannot come near this, becaufe 
we have already fhewn, tliat the greatefl effeft is produced, 
when the velocity of the wheel is two-fifths of the velocity 
of the moving water. The water, after it has finifhed its 
effeft, is difcharged with that velocity ; hence it retains 
and carries away with it three-fifths of its original power. 
Neither can we obtain the full effeft of the weight of the 
water, for another lofs is fuftained, in the change of figure 
which the water experiences, when it flnkes the float-board. 
This is much greater than is ufually fuppofed, in confidering 
machines, although it mull be familiar to any one who con- 
fiders the refiftance of a boat, or other body, when drawn 
through water. No weight is raifed in thefe cafes, unlefs 
the motion be rapid, ( fo as to raife a wave before the moving 
body ; ) but all the power is expended in changing the figure 
of the water, by dividing the particles, and putting them 
in new pofitions, fo that tiie body can pafs between them. 

It is to this fource that we mult look, for the difference 
between two-fifths of the power, which we find is abftrafted 
from the whole power of the w.iter by an underfhot-wheel, 
and one-third of the power, which is the utmofl we can ob- 
tain by means of an underfhot wheel. 

In the other clafs of machines, which are aftuatcd by the 
weight of water, wc can obtain a much greater fl^are of the 
power of the defcending water. The weight of the water 

is borne by the machine, which muft therefore receive the 
whole weight of the water, and the lofs is chiefly in the 
motion which the water ftill retains after departing from or 
quitting the machine ; but as we are not confined, as in the 
former inflance, to any fixed velocity of motion for the 
wheel, we may make it move almoft as flowly as we pleafe, 
fo that the water will carry away with it a very fmall fhare 
of the velocity which it would have acquired by falling 
through the height of the fall. Indeed, if we could fup- 
pofe a wheel to be without friftion, and no water to leak 
or efcape from thofe veffels, or parts of the wheel which 
contain the water, it would be poffible to obtain an effeft 
from it very nearly equal to the power. 

BreaJl-iVhecls. — Thefe are very commonly called under- 
fhot wheels, becaufe the water runs beneath the wheel, but 
improperly, becaufe the water does not fhoot againfl the 
floats of the wheel, or at leaft the principal power is derived 
from the weight of the water. A breall-whcel partakes of 
the nature of both an overfliot and an underfiiot, and is con- 
flrufted as is rcprefentcd \njig. i. Plate I. of IVater-ivheclt. 
The lower part of the wheel is furrounded by a curved wall 
or fweep of mafonry, which is made concentric with the 
wheel, and the float-boards of the wheel areexaftlv adapted 
to the mafonry, fo as to pafs as near as polFiblo lliereto with- 
out touching it ; and the fide walls are in like manner 
adapted to the end of the float -board or fidis of the wheel, 
the intention being, tliat as little water as pofliblc fhall be 
able to pafs by the float-boards without caufing the boards 
to move before it. The water is poured upon the wheel 
over the top of the brealUng at I, the efllux from the mill- 
dam R being regulated by the fluice or Ihuttle M, which is 
placed in thediredtion of a tangent to the wheel, and is pro- 
vided with a rack N, and pinion P, by which it can be 
drawn up fo as to make any required degree of opening, and 
admit more or lefs w:iter to flow on the wheel. 

The water firft llrikcs on the float, and urges it by its 
impulfe ; but when the floats defcend into the fweep, they 
form as it were clofe buckets, each of which will contain a 
given quantity of water, and the water cannot efcape from 
thefe buckets except the wheel moves, at leall this is the in- 
tention, and the wheel is fitted as clofe as it can be to the 
race with that view. Each of the portions of water con- 
tained in thefe fpaees bears partly upon the wall of the 
fweep, and partly upon the floats of the wheel ; and its pref- 
fure upon the floats, if not exceeded by the refiftance, will 
caufe the wheel to move ; hence the aftion upon all the 
floats which are within the fweep of the breafting is by the 
weight of the water alone ; but the water is made to im- 
pinge upon the firll float-board with fome velocity, becaufe 
the furface of the water in the dam K is raifed confiderably 
above the orifice beneath the fliuttle where the water 

The upper part of the fall at I is rounded off to a feg- 
ment of a circle called the crown of the fall, and tlie water 
runs over it. The lower edge of the fliuttle when put down 
is made to fit to this curve, io as to make a tight joint ; and 
in confequcncc when the fliuttle is drawn up, the water will 
run between its lower edge and the crown in a fhect or 
ftream whicii ilnkes upon the firft float that prefcnts itfelf, 
nearly in a dircftion perpendicular to the plane of the float- 
board, or of a tangent to the wheel. The float-boards of 
the wheel arc dirci'tcd to the centre, but there arc other 
boards placed obliquely which extend from one float-board 
to the rim of llie wiieel, and nearly fill the fpace between 
one float-board and the next. Thefe arc called rifing-boards, 
and the ufc of them is to prevent the water flowing over the 
float-board into the interior of the wheel ; but the edges of 



tliefe boards are not continued fo far as to join to the back 
of the next float, becaufe that would make all the boards of 
the wheel clofe, and prevent the free cfcape of the air when 
the water entered into the fpaces between the floats. 

As the water llrikes with fome force, the rifing-board is 
very neceflary, to prevent the water from dafliing over the 
float-boards into the interior of the wheel. 

This is the form of bread-wheel employed by Mr. 
Smeaton in the great number of mills which he conftruAed ; 
but although he fpeaks of the impulfe of the water fl:riking 
the wheel, he always endeavoured to make the top of the 
breading or crown of the fail as higli as pofTible, fo as to 
attain the greateil fall and the lead of the impulfive action. 
All rivers and dreams of water are fubjeft to variation in 
height from floods or dry feafons, and in fome this is very 
confiderable ; it was therefore neceflary to make the 
crown I of the fall at fuch a heiglit as that in the lowed 
date of the water R, it would run over the crown in a flieet 
of three or four inches in thicknefs, and work the wheel. 
When the water rofe higher in the mill-dam, it would then 
have a predure to force it through, and in that cafe would 
ftrike the wheel fo as to impel it by the velocity. 

Mr. Smeaton was well aware that the power communi- 
cated by this impulfe was very fmall. In fome cafes, where 
the water was very fubjecl to variation, he ufed a falfe or 
moveable crown, that is, a piece of wood which fitted to the 
crown I, and raifed the furface thereof a foot or more, fo as 
to obtain the greated fall when the water dood at a mean 
height ; but when the water funk too low to run over this 
moveable crown, it could be drawn up to admit the water 
beneath it. This eSeA has fince been produced in a more 
perfeft manner by making the crown of the fall a moveable 
fliuttle, to rife and fall according to the height of tlie water in 
the mill-dam, by which means the inconvenience before- 
mentioned is avoided. 

Improved Breajl-'wheel, in which the Water runs over the 
Shuttle. — Fig. 7. is a feAion of one of this kind. A is the 
water which is made to flow upon the float -board B, and 
urges the wheel by its weight only, the water being pre- 
vented from efcaping or flowing off the float -boards by the 
bread or fvveep D D, and the fide-walls which inclofe the 
floats of the wheel. The upper part of the bread D D is 
made by a cad-iron plate, curved to the proper fvveep to 
line with the done-work. On the back of the cad-iron plate 
the moving fliuttle e is applied ; it fits clofe to tlie cad-iron 
fo as to prevent the water frcan leaking between them, and 
the water runs over its upper edge. F is an iron groove or 
channel let into the niafonry of the fide-walls, and in thefe, 
the ends of the Aiding fhuttle are received ; _/" is an iron 
rack, which is applied at the back of the fliuttle, and afcends 
above the water-line w]iere the pinion g is applied to it 
to raife or lower the fhuttle. The axis of the pinion is fup- 
portedin a frame of wood II; A H is a toothed feftor and 
balance-weight, which bears the fliuttle upwards, or it might 
otherwife fall down by its own weight, and put the mill in 
motion when not intended. G is a drong planking, which is 
fixed acrofs between the two fide -walls, and retains the water 
when it rifes very high, as in time of floods ; but in com- 
mon times the water rifes only a few inches above the lower 
edge of the planking. When the diuttle is drawn up to touch 
this lower edge, the water cannot efcape ; but when the 
ftiuttle is lowered down, it opens a fpace e through which 
the water flows upon the float -boards of the wheel. This 
was tlie form firft adapted for the faliing-fliuttle, but its 
condruftion has f;;::ce been much improved. 

Fig. if. Plate II. is a fection of the moil improved form 
for a bread-wheel, taken fkini the Royal Armoury Mills, at 


Enfield Lock, erefted by Meflrs. Lloyd and Oftcl. The 
general defcription of this, is like the former, but it is con- 
druftcd in a better manner, and unites drength with dura- 
bility. The bread of mafonry is furmounted by a cad-iron 
plate A 2:t feet high, wiiich is let into the mafonry of the 
lide walls at each end, and the lower part is formed with a 
flanch, by which it is bolted to the done-bread at top. 
This plate is made draight iit the back for the fliuttle B to 
lie againd, and it Aides up aid down. The ends of the gate 
are guided by iron groove pijces or channels which are let 
into the done-work of the fide wails, and being made wedge- 
like, they fix the ends of the cad -iron bread fad in its place. 
The grooves are not upright, but inclined to the perpendicu- 
lar fo much, that the plane of the gate is at right angles to 
a radius of the wheel drawn through the point where the 
water falls upon the wheel. D is a drong plank of wood, 
extended between the iron grooves jud over the fliuttle. 
When the fliuttle is draivn up it comes in contact with the 
lower fide of this piece of wood, and dops the water ; but the 
piece D is fixed at fuch a height, that the water will run 
clear beneath it, unlefs its furface rifes above its meau 

The float-boards of the wheel do not point to the centre 
of the wheel, but are fo much inclined thereto that they are 
exaftly horizontal at the point where the water fird flows 
upon them. In this way, the gravity of the water has its full 
effeft upon the wheel, and the boards rife up out of the 
tail-water in a much better pofition, than if they pointed to 
the centre of the wheel ; and this is more particularly ob- 
fervable when the wheel is flooded by tail-water penned up 
in the lower part of the race, fo that it cannot run freely 
away from the wheel. The dimenfions of this wheel are as 
follow: — Diameter 18 feet to the points of the floats, and 14 
feet wide ; the float-boards are 40 in number, each 1 6 inches 
wide, and each rifing-board 11 inches wide. The wheel is 
formed of four cad-iron circles or wheels, each 14 feet 8 
inches diameter, placed at equal didances upon the central 
axis, which is 14 feet 8 inches long between the necks or 
bearings, and 9 inches fquare ; the bearing-necks are 9^ 
inches diameter. The wheel is calculated to make four re- 
volutions per minute, which gives near 3 j feet per fccond for 
the velocity with which the float-boards move. The fall 
of water is fix feet, and the power of the wl.eel, when the 
fliuttle is drawn down one foot perpendicular, equal to 
zB-horfe power, 

Brea/l-Wheel with two Shuttles. — In this wheel the piece 
of wood marked D in the laft figure, is fitted into the groove 
of the fliuttle, and is provided with racks and pinions to 
Aide up and down, independently of the lower fliuttle. 
The intention of this is, to make the lower fliuttle rife and 
fall, according to the heiglit of the water, fo that the water 
fhall always run over the top of it, in the proper quantity 
to work the mill with its required velocity, whild the upper 
fliuttle is only ufed to dop the mill by fliutting it down 
upon the lower fliuttle, and preventing the water from run- 
ning over it. This plan is ufed when the mill is to be regu- 
lated by a governor, or machine to govern its velocity ; in 
that cafe the governor is made to operate upon the lower 
fliuttle, and will raife it up, or lower it down, according as 
the mill takes too much or too httle water, and this regulates 
the fupply ; but the upper fliuttle is ufed to dop the mil!, 
and by this means the adj ailment of the low^r fliuttle is not 
deflroyed, but when fet to work again, it will move with its 
required velocity. Fig. 3. Plate II., Waler-whesh, is a fec- 
tion of one of the water-wheels at the cotton-mills of Meflrs. 
Strutt, at Belper, in Derbyfliire. The width of this wheel 
is very great, and to render the (tuttles A B firm, a drong 
M gra'-iag 


jjratjng of call -iron, is fixed on the top of the brcaft K, and 
the (huttlcs are appUed at the back of the grating E, fo as 
to Aide up and down agaunft it, the drain occafioned by the 
preffure of the water being borne by the grating. The 
lower (huttlc i? moted by means of long Icrcws, a, which 
have bevilled wheels, b, at the upper ends, to turn them, 
by a conneftion of wheel-work with the wheel-work of the 
mill. The upper fhuttle, A, is drawn up or down by 
racks and pinions, r, which are turned by a winch, or handle. 
The bars of the grating E are placed one above the other, 
like (heh-es, but are not horizontal ; they are inclined, fo 
that the upper furfaces of all' the bars form tangents to an 
imaginary circle of one-third the diameter of the wheel 
defcribed round the centre thereof. Thcfe bars are not 
above half an inch thick, and the fpaces between them are 
2^ inches. The bars are of a confiderable breadth, the ob- 
jeft of them being to lead the water, with a proper flope, 
from the top of the lower fhuttle A to flow upon the floats 
of the wheel. This difpofition allows the fhuttles to be 
placed at fuch a diitance from the wheel as to admit very 
llrong upright bars of caft iron to be placed between the 
wheel and the fhuttles, for the fhuttles to bear againft, and 
prevent them from bending towards the wheel, as the great 
weight of water would otherwife occafion them to do. 
Thefe upright bars are very firmly fixed to the ftone-work 
of the breaft at their lower ends, and the upper ends are 
fattened to a large timber, D, which is fupported at its 
ends in the fide walls, and has a trufs-framing applied to the 
back of it, like the framing of a roof, to prevent it from 
bending towards the wheel. The upright bars are placed 
at diftances of five feet afunder, fo as to fupport the lliu't- 
tles in two places in the middle of their length, as well as 
at both ends ; and large rollers are apphed in the fhuttle, 
where it bears againfl thefe bars, to diminifh the friftion, 
which would otherwife be very great. 

Thefe precautions will not appear unnecefTary when the fize 
of the work is known. The wheel is 2l§ feet in diameter, 
and 15 feet broad ; the fall of water is 14 feet, when it is at 
a mean height ; the upper fhuttle is 2\ feet high, and 15 feet 
long ; the lower fhuttle is 5 feet high, and the fame length, 
fo that it contains 75 fquare feet of furface expofed to the 
prefTure of the water : now taking the centre of prefTure at 
two-thirds of the depth, or 35- feet, we find the prefTure equal 
to that depth of water aftingon the whole furface ; that is, 
the weight of 35- cubic feet of water = 208 lbs. bears on 
every fquare foot of furface, which is equal to 15,600 lbs., 
or near 7 tons on the lower fhuttle only ; but if we take the 
two fhuttles together, the furface is I }f. fquare feet, and 
the mean prefTure 312 lbs. upon each, or 16 tons in the 
whole. The wheel has forty float-boards pointing to the 
centre. The wheel is made of cafl-iron. There are two 
wheels of the dimenfions above flated, which are placed in a 
line with each other, and are only feparated by a wall which 
fupports the bearings ; for they work together as one wheel, 
and the feparation is only to obviate the difficulty of making 
one wheel of fuch great breadth as 30 feet, though this is 
uot impoffible, for there is a wlieel in the fame works 40 feet 
in breadth, but it is of wood and not in iron, framed in a 
particular manner, as we fhall foon defcribe. 

Mr. Buchanan's Bucket IValer-lVheel for a low Fall. — We 
have already fhewn, that where water can be made to aft 
on a wheel by weight, it is much more cfTeftual than when 
the fame water is made to aft by impulfe ; and we fhall fhew 
this more fully in fpcaking of overfhot-wheels. 

Where the fall is lefs than half tlie diameter of the 
wheel, if the buckets are made in the ufual form of the 
buckets for overfhot-whccls, the difficulty of filling them 

with water, and the fhort time they are able to retain the 
water, are fuch great defcfts, that in fuch cafes breafl- 
wheels, with open float-boards, fuch as we have defcribed, 
have been found in praftice to be more advantageous than 
bucket -wheels. 

Mr. Buchanan fuggefts, that, by adopting another form 
of the buckets, they might be fo made as to be eafily filled, 
and at the fame time capable of retaining the water in a 
fituation to produce nearly its full effeft altogether by 
weight, on a low fall. 

In a wheel of this conflruftion, contrary to the ufual 
praftice, the water muft be poured into the buckets from 
within the circle of buckets inllead of from without the cir- 
cle of buckets. How the filling of the buckets from with- 
in can be accomphfhed may not at firft be obvious ; but it 
may be done without the pentrough, which fupplies the 
water, making any interference with the arms of the wheel, 
if it is conflrufted as fhewn in_^^j. 4. and 5. Plalel. IValer- 
luheeh. Fig. 4. is an horizontal fcftion of the wheel> and 
plan of the pentrough ; and Jig. 5. an elevation of the 

The buckets in the figure, empty themftlves by means of 
apertures on the outfide of the wheel, which are the whole 
length of the buckets, but no wider than jufl fufficient to 
difcharge the water from the buckets when they arrive at 
the bottom of the wheel, and before they begin to afccnd. 
A A is the pentrough, into which the fupply of water is 
condufted. From B to C a part of the wheel is rcprefented, 
with the fhrouding removed, to fhew the form of the 
buckets, and the fituation of the water in them ; a, a, a, are 
the apertures by which the water efcapes from the buckets ; 
b the aperture by which the water enters from the pentrough 
to the buckets. The plan, jff . 4., fhews, that the arms, N N, 
of the wheel, and the circular rims which fupport the 
buckets, occupy only a fmall part of the breadth of the 
circular ring of buckets M ; fo that about one-third of the 
length of the buckets at each end is expofed on the infide 
of the circle, and againfl thefe parts the penflock is applied, 
as fhewn at A A, and the arms and rim of the wheel, move 
clear of it ; but the buckets, as they pafs, receive water, 
which flows in a continual flream at the orifices, b, b, of the 
pentrough ; the buckets there become filled from the infide. 
The partition-boards or plates which form the buckets are 
reprefented by the white hnes in Jig. 5., and are fo fhaped, 
that they will retain nearly the whole of the water until they 
arrive at the lowefl a ; the water then begins to efcape, and 
by the time that each bucket arrives at the lowefl point of 
the wheel, it will have difcharged all the water, and will rife 
up empty. 

This is a truly ingenious contrivance ; but we fear that in 
the execution it would prefent many difficulties, particularly 
the ring of buckets M, which could not, we think, be fo 
firmly affixed, fupported by the narrow bearing of the two 
rings and arms N, as to prefcrve their circular figure for 
any great length of time ; and any bending or warping of 
fuch a heavy mafs as a water-wheel will foon deflroy it. 
Neither is the advantage which could be derived from re- 
ceiving the water in clofe buckets, inltead of open float- 
boards, fo great as is generally imagined. 

On the Power and Effen of Brcajl-'wheeh — We fhall 
fully examine the different effefts of the power of water, 
when afting by its impulfe and by its weight, under the 
title of ovcrjhot-iuhceh. In breafl-wheels of the common 
conflruftion, the effefts of impulfe and weight arc com- 
bined ; but what is there defcribed being carefully attended 
to, the application of the fame principles in thefe combined 
cafes will be eafy. 



All kinds of machints, where the water cannot defcend 
tlirough a given fpace, unlefs the wheel moves therewith, 
are to be confidered as of the fame nature with overfliot- 
wheels, and equal in power and effeft to an overfhotAvheel, 
in which the perpendicular height that the water defcends 
from is the fame. All thofe machines that receive the im- 
pulfe or (hock of the water, whether in an horizontal, per- 
pendicular, or oblique direftion, are to be confidered of tlie 
fame nature as underfhot-wheels. Therefore, in a wheel 
which the water ilrikes at a certain point below the fur- 
face of the water in the mill-dam, and after that de- 
fcends in the arc of a circle, preffing by its gravity upon the 
floats of the wheel, the power will be equal to the effedt of 
an underfhot-wheel, whofe fall is equal to the difference of 
level, between the furfece of the refervoir and the point where 
it ftrikes the wheel, added to that of an overfhot, whofe 
height is equal to the difference of level between the point 
where it ftrikes the wheel and the level of the tail-water. 

It is here fuppofed that the wheel receives the ftiock of the 
water at right angles to its radii, and that the velocity of its 
circumference is properly adapted to receive the utmoft ad- 
vantage of both thefe powers; otherwife a reduttion muft 
be made on that account. 

Mr. Oftel, an experienced engineer, informs us, that the 
velocity of the water-wheel's circumference (hould always be 
between three and four feet ^fr fecond ; but he has not been 
able to determine which of thefe two velocities is the beft, 
except in cafes where a wheel is fubjeft to be flooded by 
tail-water ; and in that cafe four feet per fecond is belt, 
Mr. Snieaton advifed 35 feet. 

On cuerfjot Water-Wheeb — An overfliot-wheel is fimply 
a circular ring of open buckets, fo difpofed round the cir- 
cumference of a vertical wheel, as to receive the water from 
a fpout placed over the wheel in fuch a manner, that the 
buckets on one iide of the wheel fliall be always loaded with 
water, whilft the other fide is empty : in confequence, the 
loaded fide will caufe it to defcend ; and by this motion the 
water runs out ot the lower buckets, while the empty 
buckets of the rifing fide of the wheel, in their turn come 
under the fpout, and are filled with water. 

A machine fo fimple does not appear to prefent any diffi- 
culties in its execution, which fhould require any application 
of theoretic reafoning to remove them ; but in reality it is 
a matter of fome delicacy to conftrudt a wheel in fuch a man- 
ner as to obtain the greateft effeft from a given fall of water. 
It is probable, that the earlieft overlhot water-wheels con- 
fifted of a number of wooden boxes or bowls, fallened on 
the circumference of the wheel ; but thefe would foon give 
place to a better mode of conftruftion, in which the cir- 
cumference of the wheel being furrounded by a circular 
ring at each fide, the fpace between them was divided into 
feparate buckets by partition-boards. Thefe partitions 
did not point to the centre of the wheel in the direc- 
tion of radii, but were inchned thereto nearly in an angle 
of fony-five degrees. By this means, the water which 
iffued from the fpout of the trough above, nearly in an 
horizontal direftion, as a tangent to the wheel, would run 
into the buckets, and fill them as they arrived in fucceflion 
at the top or higheft point of the wheel ; but as the 
buckets changed their pofition by the defcending-motion 
of one fide of the wheel, they would become inclined, and 
the water contained in the buckets would begin to run 
over the edges of the partitions between the buckets, and 
by the time the bucket arrived at the bottom point of the 
wheel, the whole of the water would be run out and leave 
the bucke^ empty, and they would remain empty whilft 
they afcended on the oppofit-e fide of the wheel. By this 

means, a conftant preponderance of one fide of the wheel 
would be kept up by the water falling into the buckets at 
the top of the wheel, and flowing from it at the bottom. 

The points chiefly to be confidered in conftrufting an 
overftiot-wheel are, firft, that the water fhall be applied 
on the circumference of the wheel, fo as to be incapable 
of defcending without communicating motion to the wheel, 
until the water has defcended to its loweft pofition, and 
that it fliall then quit the wheel entirely ; fecondly, that 
the utmoft height of fall fliall be attained and ufefully em- 
ployed ; and thirdly, that the load or refiftance to the 
motion of the wheel fliall be fo adapted and proportioned 
to the weight of water which is applied in the defcending- 
buckets of the wheels, that the wheel will move llowly ; 
becaufe we have before ftiewn, that whatever velocity the 
wheel moves with, fo much velocity the water muft retain 
when it quits the wheel, and will thus carry away fome 
power with it. 

We fhall now proceed to conCder all the particulars 
wliich contribute to the attainment of thefe objefts, taking 
Mr. Smeaton for our guide, and only adding fuch obfer- 
vations as appear neceffary to render his maxims more 

I. On the maximum EffeB ivh'ich can be obtained from a 
Fall of Water by Means of an overjliot- Wheel. — The effeSive 
power of the fall of water muft be reckoned upon the 
whole defcent, becaufe it muft be raifed that height, in 
order to be in a condition to produce the fame effeA a 
fecond time. The ratio between the powers of the falling 
water fo eftimated, and the mechanical effefts produced 
by the wheel at the maximum, deduced from the mean 
of feveral of Mr. Smeaton's experiments, is as 3 to 2 
nearly. We have before, in our obfervations upon the 
efFetts of underfhot-wheels, fliewn that the general ratio of 
til ■ power to the effeft, when greateft, was 3 : i. The 
effeft, therefore, produced by an overfhot-wheel, under the 
fame circumftances ot quantity and fall of water, is at a 
medium, double that produced by an underfhot. From 
this, it appears that non-elaftic bodies, when afting by their 
impulfe or collifion, communicate only a part of their ori- 
ginal power ; the other part being fpent in changing their 
figure in confequence of the ftroke. 

The ratio of the power to the effeft, computed upon the 
height of the wheel only, was, at a maximum, as 10 : 8, 
or as 5 : 4 nearly, becaufe Mr. Smeaton made the wheel of 
a lefs height than the fall of water, in order to allow fome 
run or defcent of the water through the fpout or trough, 
which conducted it into the buckets of the wheel. We 
find the ratio, between the power and effeft, to continue 
the fame, in cafes where the conftruftions are fimilar; hence 
we muft infer, that the effefts, as well as the powers, are as 
the quantities of water and perpendicular heights multiplied 
together refpeftively. 

II. On the mofl proper Height of the Wheel, in Proportion 

to the tuhole Defcent The preceding obfervation fhews, that 

the effeft which can be obtained from the fame quantity of 
water, defcending through the fame perpendicular fpace, is 
double when it is made to aft by its gravity upon an over- 
fhot-wheel, to what could be obtained from it when made 
to aft by its impulfe upon an underfhot-wheel. 

Hence it follows, that the higher the wheel is, in propor- 
tion to the whole defcent, the greater will be the effeft ; 
becaufe an overfhot-wheel depends lefs upon the impulfe of 
the water when it firft ftrikes the wheel, and more upon the 
gravity of the water in the buckets. The water which is con- 
veyed into the buckets can produce very little effeft by its 
impulfe, even if its velocity be great ; both on account of 
M 2 the 


the obliquity with which it (Irikcs the buckets, and in confe- 
quonce of the lofs of water occalioned by a confiderable 
quantity of fluid being daflieJ over their fides. Inllcad, 
therefore, of expefting an incrcafe of effeft fron:i the im- 
pulfe of the water occafioned by its fall through fomc part 
of the whole height, we ftiould caufo it to aft through as 
much as poflible of this height by its gravity, by making 
the diameter of the wheel as great as pofTiblc. But a dif- 
advantagc attends even this rule ; for if the water is con- 
veyed into the buckets with a very fmall velocity, which 
mufl be the cafe when the diameter of the wheel equals the 
height of the fall, the velocity of the whcL-l will be re- 
tarded by the impulfe of the buckets ftriking againft the 
water, in order to put it in motion, and much power would 
be loft by the water dafhing over them. In order, there- 
fore, to avoid all inconveniences, the diftance of the fpout 
from the receiving-bucket rtiould, in general, be about two 
or three inches, that the water may be delivered with a velo- 
city a little greater than that of the wheel ; or, in other 
■words, the diameter of an overfhot -wheel fhould be two or 
three inches lefs than the greated height of the fall ; and 
yet it is no uncommon thing to fee the diameters of thefe 
wheels fcarcely one-half of that height. In fuch a con- 
ftruftion, the lofs of power is prodigious. 

It is always defirable that the water fhould have fome- 
what greater velocity, than the circumference of the wheel 
in coming thereon, othcrwife the wheel will not only be re- 
tarded by the buckets ftriking the water, but thereby dafh- 
ing a part of it over fo much of the power is loft. 

The velocity that the circumference of the wheel ought 
to have, will be known by what we ftiall fay next, and the 
depth of column requifite to give the water its proper velo- 
city, is eafily computed from the rules and tables given in 
this article, and will be found much lefs than what is gene- 
rally fuppofed. 

This maxim obliges us to ufe a wheel, whofe diameter is 
nearly equal to the whole fall ; but we fhall not gain any 
thing by employing a larger wheel. It is true, we could 
then apply the water upon a part of the circumference 
where the weight will aft more perpendicularly to the ra- 
dius, but we ftiould lofc more, by the neceffity of difcharging 
the water at a greater heiglit from the bottom, becaufe the 
water, in all cafes, begins to run out of the buckets long 
before they arrive at the bottom of the wheel. 

Suppofe the buckets of both wheels equally well con- 
ftrufted in either cafe, whether the wheel is only as liigh as 
the fall, or of a greater height, then the heights above the 
bottom, where they will difcharge the water, will incrcafe 
in the proportion of the diameter of the wheel. That we 
/hall lofe more by this, than we gain by a more direft appli- 
cation of the weight, is plain without any further reafoning, 
by taking the extreme cafe, and fuppofing our wheel en- 
larged to fuch a fize, that the ufelefs part below would be 
equal to our whole fall. In this cafe, the water would be 
fpilled from the buckets as foon as it is delivered into them. 
AH intermediate cafes, therefore, partake of the imperfec- 
tion of this. It was the objeft of Mr. Buchanan's bucket- 
wheel, which we have already defcribed, to avoid this dif- 
ficulty, and employ a height of fall which bore only a fmall 
proportion to the whole height of the wheel. This obfer- 
vation necellarily leads us to confider the beft form for the 

III. On the hejl Form for the Buckets of overjhot IVheeli 

It IS impolTiblc to conftruft tlie buckets fo that they will re- 
main completely filled with water till they reach tlie bottom 
of the wheel : indeed, if the buckets were formed by par- 
titions direftcd to llit axis of the wheel, the whole water 

muft run out by the time they have defcended to the level 
of the axis ; and, in confequence, there muft be a great 
diminution in the mechanical cffeft of the wheel. Mill- 
wrights have, therefore, turned their chief attention to the 
determination of a form for the buckets which fhall enable 
them to retain the water throhgh a great portion of the 
circumference of the wheel. An infpettion of Jt^s. 2 and 3 
will fhew at once the proper form which has been cftablifhed 
by long praftice. Thefe are called elbow-buckcts, be- 
caufe each partition is formed by two boards, which are 
put together with an angle or elbow. The rule for fctting 
thefe out is, to divide the wheel into the number of buckets 
it is intended to have ; then take four-fifths of the fpace or 
interval between two partitions for the depth of the (hroud- 
ing, that is, the breadth of the circular rings at the fides of 
the wheel, which form the ends of the buckets, and arc 
called the flirouds ; whilft the planking, which forms the 
bottom of all the buckets, is called the fole of the wheel. 
That board of each partition which is in the direftion of a 
radius to the wheel, riles from the fole half the depth of 
the fliroud ; the other board of the bucket is fo inclined, 
that its outer end fhall be advanced beyond the line of the 
next radius-board, if it was produced. 

It is a great advantage to make the partitions of the buckets 
thin, particularly the edges of the partitions, which will 
meet and divide the ftream of water flowing upon the wheel ; 
and if thefe edges are not made fharp, they will fplafli the 
water about ; the edges are, therefore, finiflicd by iron- 
plate, or it is better to make all the inclined parts of the par- 
tition of iron-plate. The greater number of buckets, and 
the fliallower they are, the more regularly the wheel will 
aft. The limits are, that the mouths of the buckets fhall 
be of fuch width as to allow the air to cfcape, at the fame 
time that the ftream of water flows in ; and alfo that the 
breadth of the wheel fhall not be extravagantly great, to 
make its buckets contain as much water as would produce 
the power required from the wheel. 

The lofs of water, at the lower part of the wheel, will 
very much depend upon tlie proportion of water which is 
poured into cacli bucket. It is evident, that if the buckets, 
of whatever form they are made, were totally tilled when at 
the top of the wheel, they muft begin to fpill the water im- 
mediately when they departed from that pofition. But, on 
the other hand, if only a part of the content of each bucket 
is filled with water, then it will bear a greater degree of in- 
chnation, and be a longer time before the water will begin 
to fpill from the bucket. This is a reafon for making large 
buckets, and filling only a part of their contents. In prac- 
tice a medium muft be ftruck between thefe contending cir- 
cumftances, and the wheel will aft to advantage. 

It has been propofed to apply anotlier bend to the parti- 
tion-boards of each bucket which ftiall be beyond the in- 
chned board that we have defcribed, and fhall be concen- 
tric with the rim of the wheel, in the fame manner as i* 
reprefcnled in Mr. Buchanan's whcel,y?f. 5. It is true 
that this form would retain the water from fpiUing for a 
longer time, and thus be an advantage ; but it is not favour- 
able for admitting the water into the buckets when at the 
top of the wheel. 

The inclined boards, when made as we have defcribed, 
may be cxaftly in the Une of the ftream of water, which 
iffues from the fpout when it pafles beneath fuch ftream ; 
and in this way, if the edge of the inclined board is made 
thin, there will be as little fplafliing of the water as poflible. 
But by the addition of another part to the edge of tlie par- 
tition, which is concentric to the circle of the wliccl, the 
ftream of water cannot be made to proceed cxaftly in the 



line of the partition, and will therefore fplalli the water. 
The fplafhing may appear immatei-ial, but it is in rcahty 
very prejudicial, bccaufc tlie broken water fills the mouth 
of the bucket, and prevents the air from getting out rea- 
dily, and it is for this reafon that it is very ncceflary to 
allow fo much of the fall above the height of the wheel, as 
will make the water run into the buckets, with a little 
greater velocity than the motion of the wheel. 

Dr. Robinfon, in the Encyclopjedia Britannica, defcribed 
a plan for the buckets of an overfhot wheel, which was in- 
vented by Mr. Robert Burns, millwright, and executed by 
him at a cotton-mill in Scotland : it is fhewn mjig. 5. Plate \\. 
IVater-wheeh. In this way, the wheel has two ranks of 
buckets, one within the other. The buckets confift of a 
partition A B, in the direftion of a radius of the wheel, 
which is joined to another B C, inclined to that, and alfo 
to a third C D, which is concentric with the rim of the 

The bucket is divided into two, by a partition L M, alfo 
concentric with the rim of the wheel, and fo placed as to 
make the inner and outer portions of the bucket nearly 
of equal capacity. It is evident, without any farther reafon- 
ing, that this partition will enable the double bucket to re- 
tain its water much longer than the fingle one could. When 
they are filled only one-third, they retain the whole viater 
at eighteen degrees from the bottom of the vyheel, and they 
retain half of the water at eleven degrees. The only ob- 
jeftion is, that they do not admit the water quite fo freely 
as buckets of the common conftruftion. 

This arifes from the air, which mull find its way out to 
admit the water, but is obftruAed by the entering water, 
and occafions a great fpluttering at the entry. This may 
be entirely prevented, by making the fpout confiderably nar- 
rower than the wheel, and will leave room at the two ends 
of the buckets for the efcape of the air. It was found in 
pradfice, that a flo\K' moving wheel, allowed one half of the 
water to get into the inner buckets, efpecially when the 
partitions which form the inner buckets, did not altogether 
reach the radius drawn through the lip D of the outer 
bucket. The doftor confiders this as a very great improve- 
ment of the bucket-wheel ; and when the wheel is made of 
a liberal breadth, fo that the water may be very (hallow in 
the buckets, it feems to carry the performance as far as it 
can go. Mr. Burns made the firil trial on a wheel of 
twenty-four feet diameter, and its performance is manifeftly 
fuperior to that of the wheel which it replaced, and which 
was a very good one. It has alfo another valuable property. 
When the fupply of water is very fcanty, a proper adjuft- 
ment of the ftream of water iffuing from the fpout, will 
direft almoft the whole of the water into the outer buckets ; 
which, by placing it at a greater diftance from the axis, 
makes fome addition to its mechanical energy. 

IV. Concerning the proper Velocity of the Circumference of 
an overfhot Wheel, in order to produce the greatejl EJfed. — If a 
body of water is let fall freely from the furface of the 
water in the upper refervoir to the bottom of the defcent, 
it will take a certain time in falling ; and in this cafe, the 
whole aftion of gravity will be fpent in giving the water a 
certain velocity. But if this water in falling is intended to 
aft upon fome machine, fo as to produce a mechanical 
effeft, the falling water muft be retarded, becaufe a part of 
the aftion of gravity is then fpent in producing the effeft, 
and the remainder only will give motion to the falling water, 
which motion it will retain, after it has quitted the machine. 
On this principle, the flower a body defcends the greater 
portion of the aftion of its gravity can be applied to pro- 

duce mechanical circct, and in confequence the greater that 
effeft will be.- 

If a quantity of, water falls from a ftream, into each 
bucket of an overfhot -wheel, it is there retained until the 
wheel, by moving round, difcharges it. Now, the flower 
the wheel moves, the more water each bucket will receivt?, 
becaufe it remains a longer time beneath the fpout, fo that 
what is loft in the fpeed with which the wheel moves, is 
gained ty the preffure of a greater quantity of water afting 
in the buckets at once ; and if confidtred only in this light, 
the mechanical power of an overfliot-wheel to produce effefts 
will be equal, whether it moves quick or flow. The popular 
reafoning adduced to prove this has been of the following 
kind. Suppofe that a wheel has thirty buckets, and that four 
cubic feet of water are delivered in a fecond on the top of 
the wheel, and difcharged, without any lofs by the way, at 
a certain height from the bottom of the wheel. 

It is clear that this ftream will fupply the fame quantity, 
whatever is the rate of the wheel's motion ; and the buckets 
muft be of a fufficient capacity to hold all the water which 
falls into them when the wheel moves very flow. Suppofe 
this wheel employed to raife a weight of any kind, for in- 
ftance to draw a baflvet of coals out of a deep pit or mine, 
and that the rope winds upon a barrel of fuch fize that the 
bafliet will be drawn up with the fame velocity as the water 
in the buckets defcends. Suppofe, further, that the wheel 
will make four revolutions in a minute, or one turn in fifteen 
feconds, when the load or weight in the bafl<et which forms 
the refiftance to the motion of the machine is one-third of 
the load of water contained in the buckets of the wheel. 

Now, during the time of one revolution, fixty cubic feet 
of water will have flowed into the thirty buckets, and each 
have received two cubic feet. In this cafe, the ballcet may 
contain a weight equal to twenty cubic feet of water, which 
weight will be drawn up a height equal to one circum- 
ference of the wheel, during one turn of the wheel, or in 
fifteen feconds of time. 

Now fuppofe the machine fo loaded, by making the 
baflvet more capacious, that the wheel can only make two 
turns in a minute, or one turn in thirty feconds, then each 
defcending bucket of the wheel will receive four cubic feet 
of water. If the bafl<;et contained a double weight, w'z. 
equal to forty cubic feet, the effeft produced by the ma- 
chine would be the fame as before, becaufe the velocity is 
only one half; but we find in praftice, that it will raife 
more than in this proportion when it moves flower, for if 
we attend to what we have juft obferved of the faUing body, 
we find that fo much of the aftion of gravity as is employed 
in giving motion and velocity to the wheel and water therein, 
muft be fubtrafted from its preffure upon the buckets. 
The produft made by multiplying the number of cubic 
inches of water which aft on the wheel at once by its velo- 
city, will be the fame in all cafes ; yet, as each cubic inch, 
when the velocity is greater, preffes more lightly upon the 
buckets than when the velocity is lefs, the power of the 
water to produce effefts will be greater in the lefs velocity 
than in the greater. This leads us to the general rule, that 
the lefs the velocity of the wheel, the greater will be the 
effeft produced by any given quantity, and fall of water. 

A confirmation of this doftrine, together with the limits 
it is fubjeft to in praftice, is a matter of experiment and 
obfervation which has been ably decided by Mr. Smeaton. 
The velocity of the wheel fliould not be diminiflied, further 
than what will produce fome folid advantage in point of 
power ; becaufe, as the motion is flower, the buckets mull 
be made larger, that the increafe of their weight may com- 



penfatc for the flovrnefs of their motion. The wheel being 
thus more loaded with water, the llrefs upon every part of 
the work will be increafed in proportion. 

The bell rule for praftice will be, to make the velocity 
of the circumference a little more than three feet in a 

Experience confirms, that this velocity of three feet in a 
fecond, is applicable to the greateft ovcrfliot wheels as well 
as the fmallelt ; and all other parts of the work being pro- 
perly adapted to this velocity, the fall of a given quantity 
of water, will produce very nearly the greateft effed pofli- 
ble. But it is alfo certain from experience, that large 
wheels may deviate further from this rule before they will 
lofe their power, by a given aUquot part of the whole, than 
fmall ones can be admitted to do ; for inftance, a wheel of 
twenty-four feet high may move at the rate of fix feet per 
fecond, without loling any confiderable part of its power. 
This may perhaps be accounted for, when we conCder how 
fmall a proportion of the whole fall is requifite to give the 
water the proper velocity which the wheel ought to have ; 
whilil in a fmaller wheel, the fame height muft be allowed 
for that purpofe, and confequently, a greater proportion of 
the whole height. On the other hand, Mr. Smeaton tells 
us, that he had feen a wheel of thirty-three feet diameter 
that moved very lleadily and well, with a velocity but little 
exceeding two in-t/i;-r jecond. 

There is a natural wi(h to fee a machine move briflcly ; it 
has the appearance ot aftivity : but a very flow motion al- 
ways looks as if the machine was overloadtrd. For this rea- 
fon, mill-wrights have always yielded flowly, and with reluc- 
tance, to the advice of Mr. Smeaton, but they have yielded ; 
and we now fee them adopting maxims of conilruftion more 
agreccye to found theory, that is, making their wheels of 
great bveidth, and loading them with a great deal of work. 
The reluftance to adopt this fyftem did not arife folely 
from prejudice, but from a real inconveaience attending 
the flow motion of the wheel when the refiftance which is 
oppofed to its motion, and which is the caufe that it 
moves flowly, is not uniform in the different parts of a 

In all machines, there are fmall inequalities of aftion 
which are unavoidable ; and in fome machines very great in- 
equalities arife, from the intermitting motions of cranks, 
ftampcrs, and other parts which move unequally or reci- 
procally. When a water-whctl is employed to give motion 
to fuch machines, it may be fo refifted or loaded, as to be 
nearly in equilibrio with . its work, in the moft favourable 
pofition of the parts of the machine ; but when thefe change 
into a lefs favourable pofition, the machine may flop the 
wheel altogether, or at all events hobble, and work very 
irregularly. And for the fame reafon that a water-wheel 
accommodates its motion very quickly to the refiftance it 
is to overcome, fo all tendency to irregular motion is in- 
creafed. A wheel, when its load is increafed, moves more 
flowly, and receives more water into each bucket ; thereby 
taking to itfclf a weight of water equal to overcome its 
load, and on the other hand by moving quicker, it takes 
lefs water into each bucket when the load is diminiflied. 
But thefe changes do not take place inftantaneoufly, be- 
caufe it can be only in the moment that each bucket pafles 
beneath the ftream, that the fliare of water it fhall have, 
will be influenced by the rate of the wheel's motion. 
When a bucket is once filled it continues with that charge 
until it arrives at the bottom of the wheel. 

This felf-rcgulating property of the wheel can only ap- 
ply in cafes of fmall and permanent changes of refiftance. 

for it always comes too late to correft fiidden and confider- 
able changes in the refiftance ; then it afts in the contrary 
direftion. Suppofe, for inftance, nn oveifliot wheel is em- 
ployed to work a fiiigle pump by means of a crank, the 
refiftance of this macliine will be continually varying ; it 
will be nothing during one-half of the period of the revo- 
lution when the pump is not drawing any water, and during 
the other half it will be in a conftant ftate of increafe and 
diminution. Now, during the time this wheel has nothing to 
do, it will turn round very quickly, and therefore each 
bucket will receive very little water ; confequently, when 
the wheel comes to be refifted, the wheel will have fo little 
water in its buckets, that it will perhaps be quite ftopped: 
in this cafe, the bucket beneath the fpoiit will receive water 
until it is quite full, and then the water will run over and 
fill fo many of the buckets beneath it, as to put the wheel 
in motion flowly ; ii. confequence, the fucceeding buckets 
will receive a large fliare of water during the half revolu- 
tion when the pump makes its ftroke ; but when this is 
finiflied, and the refiftance ceafes, the wheel being well 
loaded with water, will in confequence move very rapidly 
for a half revolution, and its buckets will receive very little 

This is indeed an extreme cafe of irregular refiftance, 
and muft be remedied by applying two pumps inftead of 
one, or a halanc»-weight, or a fly-wheel ; but the fame 
principle will apply in cafe of fmaller irregularities. In all 
cafes, the refiftance muft be reduced to a great degree of 
uniformity, before a water-wheel can be applied to it with 
advantage, particularly if the wheel is intended to move 
flowly, with a vie%v of obtaining the greateft power, the 
irregularities will then have more ferioui confequenccs. 

A little more velocity enables the machine to overcome 
tliofc increafed refiftances by its inertia, or the great quan- 
tity of motion inherent in it. Great m-ichines pofl^efs this 
advantage in a fupcrior degree, and wi" confequently work 
fteadilywilh a fmaller velocity. In all cafes, the machine 
muft have fo much moving matter in it ;is is fufficient to 
overcome the irregularities, and regulate the motion of the 
wheel. If this is not already found in the machine, as in the 
mill-ftones of a corn-mill for inftance, the weight muft be 
placed in the water-wheel itfelf, or in a fly-wheel appUed 
for tiie purpofe. 

Mr. meafured the quantity of water which a 
cotton-mill required, when going at its common velocity ; 
and when going at half that velocity. The refult was, tliat 
the laft required juft half the quantity of water which the 
firft did. In the experiments, the quantities of water were 
calculated from the depth of water and apertures of the 

From which experiments, he inferred that the quantity 
of water neccflary to be employed in giving different de- 
grees of velocity to a cotton-mill, muft be nearly as the 
velocity. The water from the cotton-mill on which he made 
the observation, falls a little below it, into a perpcndicular- 
fided pond, which ferves as a dam for a corn-mill. Bymea- 
furing the time which the water took to rife at a certain 
height in that pond, he determined the expenditure of water 
when the corn-mill moved at its common velocity ; and alfo 
when it moved at nearly half that velocity. 

The refult of thefe experiments approached very nearly 
to the former, and all the differences could be accounted for, 
by a fmall degree of leakage, which took place at the 
fluices on the lower end of the pond ; and the time being 
greater when the mill moved flower, the leakage would of 
courfe be greater. 



In thefe experiments, the motion of the water-wheel 
being exaftly proportioned to the quantity of water ex- 
pended, the load upon the wheel muft have been equal when 
it moved quick or flow, that is to fay, the buckets muil 
have been equally filled when the wheel moved at its ordi- 
nary motion, or at half that motion. 

The eifeft, therefore, of letting more water on a wheel 
when the refinance continues the fame, is not to lodge a 
greater quantity in each of the buckets, but to fupply the 
fame quantity to each bucket when the wheel is in a 
greater motion. 

The greateft velocity that the circumference of an over- 
fliot wheel can acquire, depends jointly upon the diameter 
or height of the wheel, and the velocity of falling bodies ; 
for it is plain, that the velocity of the circumference can 
never be greater, than to defcribe a femicircumference, in 
the time that a body let fall from the top of the wheel 
would defcend through its diameter, nor indeed quite fo 
great ; as a body defcending through the fame perpendicular 
fpace cannot perform its courfe in fo fmall a time, when 
pafling through a femicircle, as would be done in a per- 
pendicular hne. Thus, if a wheel is fixteen feet one 
inch diameter, a body will fall through the line of its dia- 
meter in one fecond : this wheel, therefore, can never arrive 
at a velocity equal to the making one turn in two feconds. 
An overfhot wheel can never come near this velocity, for 
when it acquires a certain fpeed the greateft part of the 
water is prevented from entering the buckets ; and the reft, 
at a certain point of its defcent, is thrown out again by the 
centrifugal force. The velocity, when this aftion will be- 
gin to take place, depends in a great degree upon the form 
of the buckets as well as other circumttances ; fo that the 
utmolt velocity that an overfhot wheel may be capable of is 
not to be determined generally ; and indeed tlie knowledge 
of it is not at all neceffary in praftice, becaufe a wheel, in 
fuch cafe, would be incapable of producing any mechanical 

V. On the proper Load for an overjhot Wheels In order that it 
may produce a maximum EffeH. — The maximum load or re- 
fiftance for an overfliot wheel, is that which will reduce the 
circumference of the wheel to its proper velocity, of three or 
three and a half feet per fecond ; and this will be known, by 
dividing the effeft it ought to produce in a given time, by 
the fpace intended to be defcribed by the circumference of 
the wheel in the fame time ; the quotient will be the refiftance 
to be overcome at the circumference of the wheel, and is 
equal to the load required, the friftion and refiftance of the 
machinery included. 

Vr. On the greateft Load that an overjhot Wheel can overcome. 
•^The greateft load an overftiot wheel can overcome depends 
upon the magnitude of the buckets ; and the refiftance 
which will ftop the wheel, muft be equal to the effort of 
all the buckets in one femicircumference, when quite filled 
with water. 

The ftrufture of the buckets being given, the quantity 
of this effort may be afligned, but is not of much import- 
tance in praftice, as in this cafe alfo, the wheel lofes its 
power ; for though the water makes the utmoft exertion of 
gravity upon the wheel, yet, being prevented by a counter- 
balance from moving at all, it is not capable of producing 
any mechanical efFeft, according to our definition. An 
overfhot wheel, generally ceafes to be ufeful before it is 
loaded to that pitch, for when it meets with fuch a refift- 
ance as to diminifh its velocity to a certain degree, its mo- 
tion becomes irregular ; yet this never happens until the ve- 
locity of the circumference is reduced to lefs than two feet 
per fecond, where the refiftance is equable, as appears not 

only from the preceding fpecimen, but from experiments 
on larger wheels. 

VII. ConfiruBion of the Pentrough for fupplying the Water to 
ovi-ijljot Wheels — We have hitherto fpoken of the ftream of 
water, as if it iffued from a fpout nearly in an horizontal direc- 
tion, or with only fo much inclination as will make the line of 
the ftream correfpond with the direftion of the oblique part of 
the bucket-board. This is the ancient, and ftill the common 
way ; Mr. Smeaton's, which is a much better, is Ihewn in 
Jig. 2. Plate I. Water-ivheels, G reprefents the pentrough 
through which the water flows, and F F ftrong crofs-beams on 
which it is fupported ; the wheel is fituated very clofe beneath 
the bottom of the trough, as the figure fhews. E E are two 
arms of the wheel, which are put together, as fhewn in^. 7. 
D B is the wooden rim of the wheel ; the narrow circle beyond 
this is the feftion of the fole planking, and on the outfide of 
this the bucket-boards are fixed as the figure (hews ; one of 
the bottom boards, b, of the trough at the end is inchned, and 
an opening is left between that end and the other boards of 
the bottom, to let the water pafs through ; this opening is 
clofed by a Hiding Ihuttle, c, which is fitted to the bottom 
of the trough, and can be moved backwards and forwards 
by a rod, d, and lever, e, which is fixed into a ftrong axis/"; 
this axis has a long lever on the end, which, being moved 
by the miller, draws the fhuttle along the bottom of the 
trough, and increafes or diminifhes the aperture through 
which the water iffues. The extreme edge of the (huttle is 
cut inclined, to make it correfpond with the inclined part b, 
and by this means it opens a parallel pafTage for the water 
to run through, and this caufes the water to be delivered in 
a regular and even fheet ; and to contribute to this the edges 
of the aperture where the water quits it, are rendered fharp 
by iron plates ; the fliuttle is made tight where it lies upon 
the bottom of the trough by leather, fo as to avoid any 
leakage when the fhuttle is clofed. When the wheel is of 
confiderable breadth, the weight of the water might bend 
down the middle of the trough until it touched the wheel ; 
to prevent this, a ftrong beam, O, is placed acrofs the trough, 
and the trough is fufpended from this by iron bolts which 
pafs through grooves in the fhuttle, fo that they do not in- 
terfere with the motion of the fliuttle. 

Fig. 3. of the fame plate is an overfhot wheel, for which 
Mr. Nouaille took a patent in 1813 ; he recommends that 
the water-wheel be made the full height of the fall of water, 
and that the water be applied upon tlie wheel at 53 degrees 
from the vertex. The pentrough is made nearly on the 
fame plan as Mr. Smeaton's. O R is the trough, hg the 
end inchned in the direftion in which the water is intended 
to be direfted, / the fliuttle. Aiding horizontally on the 
bottom of the trough, cde the lever for drawing the (hut- 
tle, to which motion is given by a regulating fcrew a and 
nut b. 

Fig. 9. Plate II. Water-iuheels, is the method of laying on 
water, which has for feveral years been in common u fe in York- 
fliire and the north of England. In this the water is not ap- 
plied quite at the top of the wheel, but nearly in the fame 
pofition as the laft defcribed ; but the advantages of this wheel 
over all others is, that the water can be dehvered at a greater 
or lefs height, according to the height at which the water 
ftands in the trough ; but in all the preceding methods if the 
water is fubjeft to variations of height, as all rivers are, then 
the wheel muft be diminifhed, fo that in the loweft ftate of the 
water it will ftand a fuificient depth above the orifice in the 
bottom of the trough to iffue with a velocity rather greater 
than the motion of the wheel. In this cafe, when the water 
rifes to its ufual height, or above it, the increafe of fall thus 
obtained is very little advantage to the wheel ; the improved 



wheel car at all times take the utmofl fall of tlie water, even 
when its height varies from throe to four feet. A A is the 
pentrough made of call -iron ; the end of it is formed by a 
grating of broad flat iron bars, whicli are inclined in the 
proper pofition to direft the water througli them into the 
buckets of the wheel. The fpaccs between the bars are fhut 
up by a large (heet of leather, which is made fail to the bottom 
of the iron trough at a, and is applied agaiiill the bars ; and 
the prefTure of the water keeps it in cloie contr.ft with the 
bars, fo as to prevent any leakage. This is the real Ihuttlc, and 
to open it fo as to give the required dream of water to the 
wheel, the upper edge of the leather is wrapped round a 
fmaller roller b ; the pivots" at the ends of thi? roller are re- 
ceived in the lower ends of two racks, which are made to 
Aide up and down by the aftion of two pinions fixed upon 
a common axis whicli extends acrofs the trough ; this axis 
being turned, raifcs up or lowers down the roller, and the 
leather (huttle winds upon it as it defcends, or unwinds from 
it as it afcends, fo as to open more of the fpaces between the 
bars, or clofe them as it is required. In order to make 
the roller take up the leather, and always draw it tight, a 
ftrap of leather is wound round the extreme ends of the 
rollers, beyond the part where the leather (liuttle rolls upon 
it. Thefe ftraps are carried above water and apphed on 
wheels, which wind them up with a very confiderable tenfion 
by the aftion of a band and weight wrapped on the cir- 
cumference of a wheel, which is on the end of the axis of 
thofe wheels. 

The water runs over the upper fide of the roller, and flows 
through the fpaces between the grating into the buckets of 
the wheel ; the defcent of the water pafling through the 
bars, and afterwards in falling before it ilrikes the bottom 
of the bucket, is found fully fufEcient to produce the ne- 
ceflary velocity of the water, for a fall of four inches pro- 
duces a velocity of more than four feet f>er fccond. 

We recommend this as the bell method of applying the wa- 
ter, as we fee in all other forms that a much greater portion of 
the fall is given up in order to make the water flow into the 
wheel ; not that any fuch depth as is commonly given is at 
all neceflary, but the aperture in the trough mull be placed 
fo low that the water will run through it in the very lowed 
ilates of the water, otherwife the wheel mull Hop at fuch 

On the Manner of framing Water-wheels The weight of 

every wheel mull be fupported by its axis, which therefore 
demands the firft confideration. If the axis is to be of wood 
it fhould be made of a tree of hard and durable wood, of a 
length and fize proportioned to the fixe and weight of the 
wheel ; into each end a gudgeon or centre ftiould be fixed 
for the wheel to turn upon. There are two methods of fixing 
the gudgeon into a wooden axis ; one is, by forming the 
gudgeon with a crofs, which is let into the end of the tree, 
and fattened by fcrews, and the wood is compreffed round 
the crofs by two or three iron hoops, fitted on the end of 
the tree and wedged ; this is explained in the article Mill- 
IVori. The other method is, to make a llrong iron box in a 
piece with the gudgeon, into which box the end of the tree is 
received and fecured by wedges. The box being of an ofta- 
gon fhape, and tlie wood being cut to the fame figure, it 
cannot flip round within the box. 

Of late years it has been ufual to make the great axis of 
water-wheels of caft-iron, which is a very good plan, pro- 
vided the axis is made of fufficient dimenfions. This was 
firft. praftifed by Mr. Smeaton, but he was rather unfor- 
tunate, at fcvend of them broke after having been many 
years in ufe : he then employed hollow tubes of call-iron ot 
large dimenfions and confiderable thicknefs of metal. Even 

now that the ftrength of caft-iron is better underftood, it i? 
not uncommon for the axis of a water-wheel to break, par- 
ticularly in cold and frofty weather, and for this reafon fome 
millwrights ufe wrought iron, but the hollow tube is fo much 
ftronger, as to be very fecure from accident. 

In an iron axis it is advifeable to make the bearings of the 
axis clofe to the fides of the water-wheel, and leave the ends 
of the axis projcfting beyond the bearings, in order to attach 
the cog-wheel, by which the power of the wheel is to be 
communicated to other, machinery. This diminilhes the 
length of the axis between the bearings, and renders it much' 
ft.ronger ; wooden axes mud have the gudgeons at the ex- 
treme ends. 

The next point to be confidered if, the bed means of affix- 
ing the arms of the wheel firmly to the axis. If the arms 
are of wood, and the axis alfo, the mod obvious plan is to 
mortife the arms into the axis ; but this is the word method 
that can be adopted, becaufe the axis is much weakened, and 
the water being admitted into the centre of the tree caufes it 
foon to decay, nor can an arm be eafily replaced without 
taking all the wheel to pieces. 

A better way is to ufe eight-timbers for the arms, and put 
them together fo as to interfeft each other at right angles, 
(as is fhewn in_^^. 7. Plate I. ) leaving a fquare opening in the 
centre for the reception of tiie axis, which is made up to a 
fquare by adding pieces of wood to it, and the wheel is faf- 
tened on by wedges. The only objc6lion to this is, that 
the arms are weakened by interfedling each otiier, and 
they fupport the circular rim of the wheel in unequal feg- 

In Mr. Buchanan's water-wheel, which we have before 
defcribed in Jigs. 4 and 5, Plate I. Water --wheels, is a parti- 
cular condruCtion of the arms formed by tliin planks of wood. 
He dates that this plan is applicable to any kind of water- 
wheel ; and fince 1790, when he fird condruded a wheel 
with arms on that principle, a confiderable number of large 
wheels have been erefted in Scotland on the fame plan. It 
is evident that arms, fuch as are commonly fixed in mortifcs 
in the axis, are weaked in one direftion, and that commonly 
in the direAion of the drain. To remedy this defect the 
feather-pieces F F are applied all round, having their broad- 
ed ends towards the centre of the wheel, and being at right 
angles to the breadth of l!ii; principal arms. In order to 
unite them drongly to the principal arms, and conncdl the 
whole more firmly together, a ring of iron, R, is applied 
on each fide ; blocks of wood being put in t!ie vacant fpaccs 
between, and the keys or wedges, K K, bind the whole clofe 
to the axis. 

The very bed method of uniting the arms to the axis is to 
have a cad-iron centre-piece, or llrong hoop, to fit on the 
wooden axis with a broad projecting flanch round it, againll 
the flat fiirface of which tlie arms of the wheel are applied, 
and the intervals between them filled up by wooden blocks 
or wedges ; the arms and blocks are firmly bound to the iron 
flanch by iron rings applied to the arms on the oppofito fide 
to the flanch, with Icrew bolts to go through the whole. 
This fame plan is applicable to an iron axis, and will be more 
clearly undcrdood by a reference to the article Mll.L, and 
Plate XXXIV. Mechanics; but it is there defcribed that the 
broad circular flancli to fcrew the arms againd, is cad in the 
fame piece with the axis. This was Mr. Smeaton's original 
plan, but the flanch ihould be made in a feparate piece, and 
fattened on the axis with wedges ; for if cad in the fame 
piece, the contraction of the metal contained in the flanch 
when cooling, renders the metal of the axis ipongy at the part 
where it joins to the flanch, .ind caufes them to break at that 
part. Somelimcs the cad-iron cciilre-piccc is made with a 



diftiiift cell to receive each arm, and they are faflened into 
the cells by wedges and fcrew-bolts, but a flat flanch with 
the intervals filled up by blocks is more fimple and i^ecure. 
Modern wheels are very frequently made with caft-iron arms, 
which in this cafe are attached to the axis by a fimilar 

The circular rims of water-wheels are commonly made of 
wood, put together in two or three thicknefles, the joinings 
of one ring not coinciding with thofe of the other, and 8 or 
lo fegments in each thickncfs, according to the fize of the 
wheel ; the thicknefles are united together by rivets. The 
arms are attached to the ring by notching them in, and fc- 
curing them by bolts. Caft-iron rings are now generally ufed, 
and with great advantage, becauie the necelTary mortifcs 
can be made in iron, without weakening the ring ; but the 
ilrength of a wooden ring is greatly impaired by the mor- 
tifes through it. 

The number of rings in a wheel depend upon its breadth; 
when the wheel is four feet wide, two rings will fupport the 
float-boards or buckets, but the rings ihould not be more 
than five feet afunder, or the floats may bend and yield ; for 
want of a fufhrient fupport each ring is framed with its fet 
of arms, fo that every one derives its Ilrength from the 
axis. When a wheel is of great breadth, the whole will be 
very much ftrengthened, by applying obhque braces, ex- 
tending from the centre-pieces of the outfide rings to the 
circumference of the middle ring, by firmly attaching thefe 
oblique braces to the arms of all the rings which they inter- 
cept ; they form trufs-frames which prevent the wheel and 
the axis from bending by its weight ; this is particularly 
ufeful in wide overfhot wheels. 

In breaft and underfhot wheels the float-boards are nailed 
to pieces of wood called ftarts, which ai-e fixed into the mor- 
tiles in the rings, and projeft outwards for that pnrpofe. 

In overlhot-wheels, the rings of the wheels are covered by 
boards laid parallel to the axis, well jointed together, and 
fpiked down to the rings like the boards of a floor to the 
joifts. This boarding forms a clofe cylinder, which is called 
the fole of the wheel, and is the foundation for the buckets. 
When the rings of the wheel are of iron, holes are left in 
the callings in the edge of the rings, at regular diftances 
round the circumference, and thefe are filled up with plugs 
of wood, into which the nails can be driven to faften on the 
boarding of the folo. The fole of the wheel is fometimes 
made of iron plates rivetted together, and rivetted alfo to 
the rings of the wheel. 

At the ends of the fole-boards, two circular rings of 
wood or iron, called (hrouds, are fitted on perpendicularly 
to the fole to form the ends of the buckets ; and it is ufual, 
if the wheel is wide, to apply a flirouding over each ring of 
the wheel, and then the buckets are divided into lengths of 
about four or five feet. In the flat furfaces of the fhroud- 
ings, grooves are made for the reception of the ends of the 
bucket-boards. It is ufual to make the firft board, which 
is in the dii-e£lion of a radius, of wood, and the outfide one 
is generally made of iron plate ; but fometimes the whole 
are made of plate iron, and both parts of the buckets are 
then bent up out of one piece, and the ends of the plate ; and 
alfo that part of the edge which is to apply to the fole, is 
turned fqaare to lie flat againft the fole and the flirouding, 
fo that rivets and nails may unite all together, and make 
water-tight joints. 

When the flirouding is of caft-iron, it is made to ferve 
inftead of the rings of the wheel, becaufe it has fufficient 
ftrength to ferve both piu-pofes : the arms of the wheel are 
in this cafe applied flat againft the ring of flirouding, and 
bolted to it. 

Vol. XXXViri. 

The breaft -wheel,^_f. 3. Platell. Water-tuheeh, at Meflrs. 
Strutt's works, which we have already noticed, is deferving of 
further notice from the manner of putting it together. The 
rings of the wheel are made of caft-iron, and the float-boards 
are included between the rings in the manner of an overfliot 
wheel, but the arms are only of wrought iron, being made 
of fmall round iron rods, which are very light, and have little 
ftrength to refift bending ; but as they are all tied in from 
the centre, the ring cannot deviate from its true circular 
figure, and to fuftain the wheel fideways, oblique bars are 
extended from the centre-pieces at each end of the axis, and 
are united to the circular ring in the middle of its breadth, 
which is 15 feet. We have feen two overfliot-wheels of 24 feet 
diameter, and 9 feet broad, made in the fame way. It is 
plain that in this conftruftion the axis of the wheel can do 
no office but to fupport the weight of the wheel ; for though 
thefe arms are fufficiently ftrong for that purpofe, they can 
have little ftrength by way of levers to tranfmit the force 
of the circular motion of the rim of the wheel to the axis ; 
but the power is tranfmitted in a better way than from the 
axis, Ti/2. by a ring of cogs fcrewed to the circular rim of 
the wheel, and working in a pinion which conveys the mo- 
tion to the mill. There is another fimilar ring of cogs at 
the other fide of the wheel, which works into a pinion fixed 
on the fame fliaft, by this means nearly all the ftrain is taken 
from the axis of the water-wheel ; for the pinion is placed 
on the defcending fide of the wheel, fo that the weight of the 
water afting on the float -boards is immediately tranfmitted to 
the pinions by the ftrength of the rings of the wheel. 

This method of tranfmitting the power is alfo applied to 
other wheels than thofe which are made with flight arms 
hke the above ; the ring of cogs is fometimes placed in the 
middle of the breadth of the wheel, and then afts upon one 
pinion, but it is much better to place it at one fide or both 
fides, if the wheel is very broad, becaufe the circle of the 
teeth may then be made rather lefs than the diameter of 
the rings of the wheel, and the fide of the ring being clcrfely 
fitted to the ftone-work of the race, the water may be ex- 
cluded from the cogs. 

It is obvious that of the various conftruftions of water- 
wheels, that is the ftrongeft which communicates its motion 
by means of a ring of cogs immediately attached to its rim, 
where the power of the water is alfo applied, the leaft pof- 
fible ftrain being thus thrown on its arms and axis. 

The only objeaion to this plan is, that as the teeth of 
the cog-wheel are in moft cafes conftantly wet, which pre- 
vents the greafe from adhering, the ufual mode of occa- 
fionally greafing the cogs is of httle or no ufe, and the dirt 
in the water grinds away the teeth ; or, were the water even 
free from du-t, there would be much unneceflary fridion and 
wafte of power. 

Greafmg Machine for the Cog-Wheel of a Water-Wheei— 
Mr. Buchanan mentions two water-wheels of this kind, in 
which the rings of the teeth were wearing very faft, and 
knowing the trouble and expence of renewing them, he was 
folicitous to dilcover fome means of rendering them more 
durable. The only v-ay which prefented itfelf was by fome 
contrivance to keep them well greafed. 

This he did by a machine fliewn in Jig. 8. Plate I. Water- 
•wheels ; it is nothing more than a kind of pinion, with one 
or more of its teeth made hollow to contain the greafy fub- 
ftance, and the metal plate of which the hollow cog is-com- 
pofed is perforated with fmall hole?, for exudating the 
greafe through thofe parts which come in contadl with the 
teeth of the wheel. 

Fig. S. io a fcdtion of the greafing machine ; A B repre- 

fents part of the ring of teeth on the circumference of the 

N water- 


water-wheel. The greafing-pinion which works in tliefe 
teeth is mounted on an axis, as is clearly (liewn. 

N O a retarding lever, of which N is the fulcrum, and O 
a weight to make it prefs on the axis of the greafing-pinion, 
fo as to caufe a relillance, and make the cogs of the wheel 
prefs forcibly on the cogs of the pinion. 

G H I K, the iioUow teetli for containing the greafe ; 
t>iey are made of copper-plate or iron ; and to make the per- 
forated fides of the greifing leaves come in clofe contaft 
with the face of the teeth of the wheel, the lever N O, 
with a fmall weight on it, afts on a pulley fixed on the axle 
of the pinion, and ferves to retain it. 

E F, &c. the fohd teeth of the pinion, made of wood ; 
there are Aiders which open for admitting the greafe into the 
hollow teeth at their ends. 

The number of leaves in the greafer fliouid be fuch, that 
thofe containing the greafe Ihall apply themfelves in the 
courfe of feveral revolutions of the wheel to each of its teeth. 
Mr. Buchanan found a greafer of 1 2 leaves, 4 of which con- 
tained greafe, had this effeA upon a wheel of 304 teeth ; and 
one of^i3 leaves, with one tooth only filled with greafe, 
ferved a wheel of 168 teeth. 

It k beft to ufe a mixture of tallew, oil, and black lead for 
greafing, made of a coiififtency to feed regularly, and frefh- 
cned about twice in a week. 

Conjlruaion of a Breajl-Wtfte] of very great ll^iJth — At 
Meffrs. Strutt's works is a very powerful breaft-wlieel, made 
of the extraordinary width of 40 feet, and it defervesour notice 
from the manner of framing it together ; its diameter is only 
I2i feet, and it is made witliOut any axis, or rather the axis 
is hollow, and fo large that the float-boards are fixed imme- 
diately upon it. It is made like a very long cafk, 48 feet 
long, compofed of 32 (laves of fix inches thicknefs, bound 
together by hoops like an ordinary ca(l< ; it is five feet in dia- 
meter at one end and fix feet at the other, and in the middle 
7 feet 2 inches ; the fmall end is made up folid for three feet 
in length, and the gudgeon is fixed in tliis fohd part ; the larger 
end is folid for four feet from the end, and on this part the 
large cog-wheel is fixed to communicate the motion to the 
mill; it is 14 feet diameter, and has 120 cogs, whilft the 
water-wheel is only I2i feet diameter to the outfide of the 
floats. The floats are fupported by 10 circular rings, 
which are fixed on the outfide of the axis or caflv, at four 
feet diftance from each other, and the float-boards are fixed 
between thefe rings, 24 floats being arranged in each 
circle ; but the Hoats in the different fpaccs are not made to 
line with each other, bccaufe if the water was to (Irikc upon 
the whole length of 40 feet of float -board at once, it would 
give a fenfible fhock to the water-whctl, and work the mill 
irregularly ; hence the floats between all the different rings 
are placed oppofite to the intervals between the floats in the 
adjoining fpaces, by which means the water afts on the 
floats in rapid fuccclTion, fo that the ftroke upon any one 
float is imperceptible. 

The float -boards are not made to touch the central-barrel 
or axis within two inches, in order to leave fpace for the air 
to efcape. The float-boards in the middle of the wheel are 
2 feet 4 inches wide, and at the ends are wider. This wheel 
has two fhuttles, one above the other, hke the hrcaft-whecl 
before defcribed in fig. 3, and the fame dimenfions ; for the 
wheel is placed in the fame mill, but is adapted to work 
when the tail-water rifcs in time of floods to fucli a height as 
to prevent the other wheel from working. 

yf very large overfbot IVhiel. — I'he largcfl overfhot water- 
wheel of which we have heard, is that at Mr. Crawfhaw's 
iron-works at Cyfartlifa, near Merthyr Tidvil, in South 
Wale*-: it is ufed to blow air into three of the large blaft 

furnaces for fmelting iron ; the water-wheel is fifty feet in dia- 
me ter and fix feet wide : it is chiefly made of caft iron, and has 
I 56 buckets. The axis is a hollow tube, and is ftrengthened 
by twenty-four pieces of timber applied round it. On each 
end of the axis is a cog-wheel of twenty -three feet diameter, 
which turns a pinion. On the axis of thef>.' are two cranks, 
and a fly-wheel twenty-two feet diameter, and twelve tons 
weight ; each of the cranks gives motion to a lever, like that 
of a large fleam-engine, and works the pillon of a blowuig 
cyhndcr or air-p ump 5 2^ inches in diameter, and five feet llroke, 
which blows air into the furnace, both when the pillon goes 
up and down. The work on the other fide being the fame, it 
aftuates in the whole four of thefe double cy finders ; the 
wheel makes about two and a half turns per minute, and 
each cylinder makes ten flrokes. It is called jEolus, and was 
built in 1 800 under the direAion of Mr. Watkin George. 

At Aberdare, in South Wales, is an immenfe double water- 
wheel, confiflingof two wheelsof forty feet in diameter, placed 
one above the other hke the figure 8, (fee our article Ca- 
nal, ) the water from the upper one acluating the lower one, 
and both being connefted together by cog-wheels on their 
refpeftive rings. We underftand this machine has not an- 
fwered, and we only mention it as an attempt to occupy a 
fall of water of eighty feet ; in fuch cafes, the Prejfure-engine, 
defcribed under that article, is a better method, particularly 
if the work will admit of a reciprocating motion. 

Chain nf Buckets This is apphcable in many fituation* 

where there is a confidcrable fall of water. This iketch was 
taken from one in Scotland ufed to give motion to a thralhing- 
mill ; the_^^. 6. Plate I. is fo obvious as to need little explana- 
tion. The buckets C, D, G, H, &c. muft be conneAed by 
feveral chains to avoid the danger of breaking, and united 
into an endlefs chain, which is extended over two wheels 
A and B, the upper one being the axis which is to com- 
municate motion to the mill-work ; E is the fpout to fupply 
the water. The principal advantage of this plan is, that 
no water is loft by running out of the buckets before they 
arrive at the lowefl part, as is the cafe with the wheel. 
Another is, that the buckets being fufpended over the 
wheel A of fmall diameter, it may be made to revolve 
more quickly than a wheel of large diameter, and without 
increafing the velocity of the defcending buckets beyond 
what is proper for them. This faves wheel-work when the 
machine is to be employed, as in a thrafhing machine to 
produce a rapid motion. On the other hand, the fritlion of 
the chain in folding over the wheel at the lop, and feizing 
its cogs, will be very confiderable ; thefe cogs muft enter 
the fpaces in the open links between the buckets, to pre- 
vent the chain flipping upon the upper wheel. We tliink 
this machine might be much improved by contriving it fo, 
that the chain would pafs through the centre of gravity of 
each bucket, whereas in t!ie prefent form, the weight of 
each bucket tends to give the chain an extra bend. 

The Chain-Pump rtverfed has been propofed as a fubfti- 
tute for a water-wheel when the fall is very great, and we 
think it would anfwer the purpofe with fome chance of 
fuccefs. It would have an advantage over the chaia- 
pump when employed for raifing water, in the facility of 
applying cup leathers to the piilons on the chain, in the 
fame way as other pumps, which leathers expand themfelves 
to the infide of the barrel, and arc kept pcrfeAly tight by 
the prefTure of the water. In the chain-pump fuch leathers 
cannot be employed, becaufe the edges of the leather-cups 
would turn down and ftop the motion, when the cups were 
drawn upwards into the barrel. It is the defeftivc mode 
of leathering the piilons of the chain-pump which occafions 
its great firiiftion. In the motion of a machine of this kind 
9 the 


the piftons would defcend into the barrel, and might there- 
fore be leathered with cups like other pumps, fo as to be 
quite tiglit without immoderate friftion. This machine was 
propofed by a Mr. Cooper in 1784, who obtained a patent 
for it, and Dr. Robifon has again propofed it with re- 

Mechamfm for equalising the Motion of IVater-Wheeh 

When a part of the machinery of a mill is fuddenly de- 
tached from the firll mover, or fuddenly connected with it, 
the load of the machine is either increafed or diminifhed ; 
and the moving power remaining the fame, an alteration in 
the velocity of the whole will take place ; it will move 
fafter or flower. Every machine has a certain velocity, at 
which it will work with greater advantage than at any other 
fpeed ; hence the change of velocity arifing from the above 
caufe, is in all cafes a difadvantage, and in delicate opera- 
tions exceedingly hurtful. In the cafe of a cotton mill, 
for inftance, which is calculated to more the fpindles at a 
certain rate, if from any caufe the velocity is much in- 
creafed, a lofs of work immediately takes place, and an in- 
creafe of wafte from the breaking of the threads, &c. ; on 
the other hand, there mull be an evident lofs from the 
machinery moving too flow. In fteam-engines this evil is 
remedied by a contrivance called a governor, which we have 
already defcribed in our article SjEAM-Engine. 

Governors are fometimes applied to water-wheels, and 
made on various conftruclions. Smith-bellows have been 
applied to that ufe, the upper board rifing and falling on 
any augmentation or diminution of the velocity of the lower 
board, which received its motion from the mill, and forced 
air into the fpace beneath the upper board ; from this fpace 
the air was permitted to efcape by a pipe with a cock. If 
the lower board worked fafter than the air could efcape, 
the upper board would rife, but if it m.oved flower, then 
the board would fink ; and this rifing and falling was applied 
to regulate the Ihuttle of the water-wheel, not by ths: force 
of the bellows alone, but the bellows were made to throw 
the wheel-work of the mill into adlion, either to raife or 
lower the fliuttle. 

Of late years a new kind of water-wheel governor has 
been introduced, the principles of which are nearly the fame 
as the governor of a ileam-engine. It has a revolving pen- 
dulum, which receives its motion from the mill, and in pro- 
portion as the machinery moves fafter or flower, the cen- 
trifugal force afts with greater or lefs force upon the balls 
of the governor, making them approach to, or recede from, 
the perpendicular axis. This raifes or deprefles an iron crofs, 
which Aides upon the perpendicular axis of the revolving 
pendulum, and by afting on a lever, is made to engage the 
fluice with a train of wheel-work, which is kept in conftant 
motion by the power of the water-wheel. When this train is 
connefted with the fluice, it operates upon it fo as to enlarge 
or leflen the paffage of the water to the water-wheel, and by 
augmenting or leffening the quantity of water falling on the 
wheel, increafes or diminifties its fpeed. 

This fluice is made on the principle of the throttle-valve 
of fteam-engines. In order that it may be moved by a fmall 
power, it is poifed on an axis of motion pailing through the 
middle of the fluice. When it is turned edgeways to the 
ftream of water, it makes no obftruftion ; but if it is turned 
perpendicularly, it clofesthe paflageof water, or by placing 
it more or lefs obliquely, it alters Ijhe area of the palfage for 
the water. 

The axis on which the fluice turns, if horizontal, fliould 
be one -third of the height of the fluice from the bottom, in 
order that the preffure of the water above the centre may 
balance that below. 

So long as the machinery is moving at a proper velocity, 
this wheel-work of the fluice apparatus is not connefted 
with the fluice, and it remains at reft. But if the mill goes 
too flow, the crofs is depreffed, and ftriking the lever in 
an oppofite direftion, connefts the fluice with a different 
part or train of wheel-work, which has a motion in a contrary 
direftion to the former, and fo produces a contrary effeft on 
the fluice. 

The train of wheel-work is fo calculated, as to reduce 
the aftion on the fluice to a very flow motion, and it is 
found, from experience, that this is neceffary. Where the 
area of the aperture is too fuddenly changed, the effeft on the 
water-wheel would be too violent. See a more complete 
defcription of this contrivance in VoL XXIII. MlLL-^Fori. 

On the ConJlruSion of the Wheel-race and Water-courfe 

The wheel-race fliould always be built in a fubftantial manner 
with mafonry, and if the ftones are fet in Roman cement, it 
will be much better than common mortar. The earth behind 
the mafonry ftiould be very folid, and if it is not naturally 
fo, it fhould be very hard rammed and puddled, to prevent 
percolation of the water. This applies more particularly to 
breaft-wheels, in which the water of the dam or refervoir is 
ufually immediately behind the wall or breaft in which the 
wheel works, a floping apron of earth being laid from the 
wall in the dam to prevent the water leaking. The wall of the 
breaft ftiould have pile planking ( fee Canal ) driven beneath, 
to prevent the water from getting beneath, becaufe that might 
blow up the foundation of the race. The ftones of the race 
are hewn to a mould, and laid in their places with great care ; 
but afterwards when the fide walls are finifhed, and the axis 
of tlie wheel placed in its bearings, a gauge is attached to 
it and fwept round in the curve, and by this the breaft is 
dreffed fmooth, and hewn to an exaft arch of a circle : 
the fide walls in like manner are hewn flat and true at the 
place where the float-boards are to work. It is ufual to make, 
the fpace between the fide walls two inches narrower at each 
fide, in the circular part where the floats aft, than in the 
other parts. 

In fome old mills the breaft is made of wood plankiilg, 
but this method has fo little durability that it cannot be re- 
commended. In modern mills, the breaft is lined with a cafl- 
iron plate, but we do not approve of this, becaufe it is next 
to impoffible to prevent fome fmall leakage of water through 
the mafonry, and this water being confined behind the iron 
breaft cannot efcape, but its hydroftatic prefl"ure to force up 
the iron is enormous ; and if the water can ever infinuate 
itfelf behind, the whole furface of the plate rarely fails to 
break it, if not to blow it up altogether. This is beft guarded 
againft by making deep ribs projefting from the back of 
the plate, and bedding them with great care in the mafonry ; 
thefe not only ftrengthen the plate, but alfo cut off the 
communication of the water, fo that it cannot aft upon 
larger furfaces at once, than the ftrength and weight of the 
plate can refift. Stone is undoubtedly the beft material for 
a breafting. In overfhot-wheels the lofs of water, by running 
out of the buckets as they approach the bottom of the 
wheel, may be confiderably diminifhed by accurately form- 
ing a fweep, or cafing round the lower portion of the 
wheel, fo as to prevent the immediate efcape of the water, 
and caufing it to aft in the manner of a breaft-wheel, which 
has been already defcribed. While this improvement re- 
mains in good condition, and the wheel works truly, it pro- 
duces a very fenfible effeft ; but it is frequently objefted to, 
becaufe a ftick or a ftone falling into the wheel would be 
liable to tear off part of its fhrouding, and damage the 
buckets ; and again, a hard froft frequently binds all faft, and 
totally prevents the poffibihty of working during its conti- 
N 2 nuance ; 


nuance ; but we Jo not think the latter a great objeftion, 
for the water is not more liable to freeze there than in the 
buckets or on the (huttle, and may be prevented by the 
fame means, viz. by keepinp; the wlicel always in motion ; a 
*ery fmall ftrcam of water leftrunninj; all night willbefuffi- 
cient. Mr. Smeaton always ufed fuch fweeps, and with 
very good efFeA ; it is certainly preferable to any intricate 
work in the form of the buckets. 

On felling oul Waler-courfes and Dams The moll ancient 

mills were undcrfhot-wheels placed in the current of an open 
river, the building containing liie mill being fet upon piles 
in the river. It would foon be obfcrved tliat the power of 
the mill would be greatly increafed, if all the water of the 
river was concentrated to th« wheel, by making an obftruc- 
lion acrofs the river which penned up the water to a re- 
quired height ; and alfo to form a pool or rcfervoir of water. 
A (luice or {huttle would then become neceflary to regulate 
the admiflion of water to the wheel, and other fluiccs would 
be neceflary to allow the water to efcape iii times of floods ; 
for though in ordinary times the water would run over »he 
top of the obftruAion or dam, yet a very great body of 
water running over might carry away the whole work, by 
wafliing away the earth at the foot of the dam, and then 
overturning it into the e>;cavalion. This is an accident 
which frequently happens to mills fo fituated, and the danger 
is fo obvious, that mod water-mills are now removed to the 
fide of the river, and a channel is dug from the river to the 
mill to fupply it with water, and another to return the water 
from the mill to the river. The difference of level between 
thefe two channels is the fall of water to work the mill, and 
this is kept up by means of a weir or dam entirely acrofs 
the river ; but the water can run freely over this dam in 
cafe of floods, without at all affcfting the mill, becaufe the 
entrance to the channel of fupply is regulated by fluices and 
fide walls. 

The dam fhould be erefted acrofs the river at a broad part, 
where it will pen up the water fo as to form a large pond or 
refervoir, which is called the mill-pond or dam-!icad. This 
rcfervoir is ufeful to gather the water which comes down the 
river in the night, and referve it for the next day's con- 
fumption ; or for fuch mills as do not work incelfantly, but 
which require more water, when tiiey do work, than the 
ordinary itream of tlie river can fupply in the fame time. 
The larger tiie furface of the pond is, the more efficient it 
will be ; but depth will not compenfate for the want of fur- 
face, becaufe as the furface finks, when the water is drawn 
off, the fall or dtfcent of the water, and confequenlly the 
power of the water, diminifhes. 

The dam for a large river fhould be conftruftcd with 
the utmoil fohdity ; wood framing is very commonly ufed, 
but mafonry is preferable. Great care mud be taken, 
by driving pile planking under the dam, to intercept all 
leakage of the water beneath the ground under the dam, 
as that loofens the earth, and dellroys the foundation 
imperceptibly ; when a violent flood may overthrow the 
whole. It is a common prafticc to place the dam obliquely 
acrofs the river, with a view of obtaining a greater length 
of wall for the water to run over, and confequenlly prevent 
its rifing to fo great a height, in order to give vent to the water 
of a flood. But this is very objeftionable, becaufe the cur- 
rent of water conllantly running over the dam, always adls 
upon the fhore or bank of tlie river at one point, and will in 
time wear it away, if not prevented by expcnfive works. 
This difficulty is obviated, by making the dam in two lengths 
which meet in an angle ,• , the vertex pointing up the 
ftream. In this way the currents of water, commg from 
the two oppofite parts of the dam, ftrike together, and 

fpend their force upon each other, without mjurnig any 
part. A ftill better form is a fegment of a cincle, which 
has the additional advantage of ftrength, becaufe if the abut- 
ments at the banks of the river are firm, the whole dam be- 
comes hke the arch of a bridge laid down liorizontally. 
This was the form generally ufed by Mr. Smeaton. 

The foot of the dam where the water runs down fhould 
be a regular flope, with a curve, fo as to lead the water 
down regularly ; and this part (hould be evenly paved with 
ilonc, or planked, to prevent the water from tearing it up, 
when it moves with a great velocity. 

When the fall is confiderable, it may be divided into more 
than one dam ; and if the lower dam is made to pen the 
water upon t!ie foot of the higgler dam, then the water run- 
ning over the higher dam will flrike into the water, and lofc 
its force. There is nothing can fo foon cxhault the force of 
rapid currents of water as to fall into other water, becaufe 
Its mechanical force is expended in changing the figure of 
the water (fee circular rueir in our article Canal ) ; but when 
it falls upon ftone or wood, its fOrce is not taken away, but 
only reflefted to fome other part of the channel, and may be 
mad? to a6l upon fuch a great extent of furface as to do no 
very ftriking injury .'.t any one time, but by degrees it wears 
away the banks, and requires conftant repairs : for it is de- 
monilrable that, as much of the force of the water as is not 
carried away by the rapid motion with which it flows, after 
paffing the dam, muft be expended either in changing the 
figure of the water, or in wafhing away the banks^, or in 
the friAion of the w.iter running over the bottom. 

The cotton-works of Meffrs. Strutt at Belper, in Dcrby- 
(hire, are on a large fcalc, and the moll complete we have 
ever feen, in their dams and water-works. The mills are 
turned l)y the water of the river Derwent, which is very 
fubjcft to floods. The great weir is a femicircle, built of 
very fubftantial mafonry, and provided with a pool of water 
below it, into which the water falls. On one fide of the 
weir are three fluices, each 20 feet wide, which are drawn 
up in floods, and allow the water to pafs fiJeways into the 
fame pool ; and on the oppofite fide is anotlier fuch lluice, 
.t2 feet wide. The water is retained in the lower pool by 
fome obftrnftion which it experiences in running beneath 
the arches of a bridge ; but the principal fall of the water is 
broken by falling into tiie water of the pool, beneatli the 
great femicircuhir weir. 

The water which is drawn off from the mill-dam above 
the weir paffes through three fluices, 20 feet wide each, 
and is then dillributed by different channels to the mills, 
which are fituated at the fide of the river, and quite fecurc 
from all floods. There are fix large water-wheels ; one of 
them, which is 40 feet in breadth, we have mentioned, from 
the ingenuity of its conftruAion ; and another which is 
made in two breadths, of I 5 feet each, we have alfo de- 
fcribed. They are all brcatl-wheels. The iron-works of 
MefTrs. Walker at Rothcrliani, in Yorklhire, are very good 
fpecimens of water-works ; as alfo the Carron works in 

Tlic largell works for overfhot-mills are in RufTia, at 
Colpino, near St. Petcrfburgh, on the river Neva. They 
were erefted principally under the direction of Mr. Gal- 
coigne of the Carron works in Scotland, and have been 
greatly improved bv the prefcnt director, who is an engineer 
of his fchool. An immenfe dam of granite is built acrofs 
the river to pen up the water, until it makes a large refer- 
voir. The waflc and flood waters do not run over this 
dam, but are condiifted out of the refervoir by a femi- 
circular brancli of the river, and run over a great weir to 
join the original courfc of the river below the works, l^ie 



sriills are fituated in the valley below the great dam, the merit of their feveral falls of water. This alone is a very 

water being conveyed to the wheels by channels coming fufficient fecurity againrt any one being injured. Common 

through the dam, and conveyed away into a large tail bafon, bread -mills will bear two feet of tail-water, when there is 

which is the original courfe of the river. The wheels, an increafe of head, and plenty of water to be drawn upon 

which are very numerous, are all 22 feet diameter. They the wheel, without prejudice to their performance ; but 

are placed in feveral different mills, for rolhng and forging mills well conftrufted, with flow moving wheels, wiU bear 

iron and copper, boring guns, making anchors, &c. Thefe three and even four feet and upwards of tail-water. Mr. 

mills are arranged on the fides of the tail bafon, which is Smeaton mentions having feen an inftance of fix feet • and it 

navigable to bring the boats up to them. There are alfo is a common thing in level countries, where tail-water is 

two large faw-mills at the end of the femicircular channel. moft annoying, to lay the wheels from fix to twelve inches 

Thefe v/orks are very complete, owing to the excellent below the water's level of the pond below, in order to in- 

execution of the dam and water-works ; but it is not a good creafe the fall of water ; and, if judicioufly appHed, is at- 

plan to place the mills beneath the dam, becaufe if it fliould tended with good effeft, as it increafes the diameter of the 

fail, or the water pour over it by an extraordinary flood, wheel, and though it mud always work in that depth of 

the mills and buildings below would be in danger of being tail-water, it will perform full as well, becaufe the water 

carried away ; whereas, on the other conftruftion, the mills, ought always to run off from the bottom of the wheel in 

being placed at a dillance from the river, are perfeftly fafe, the fame direftion as the wheel turns. 

and would not be injured if theidam fliould be wholly carried The law refpefting mill property is by no means fettled 

away. This is not a fault imputable to the gentlemen we but is greatly influenced by the cuftom of the mills upon any 

have mentioned, as the foundations of thefe works were riverorinanydift:rid; fomefewpointshoweverareeftablilhed. 

commenced in the time of Peter the Great, and too far ad- Every one has a right to that fall which the water has, in run- 

vanced to admit of altering the plan radically, when the em- ning through his own grounds, and may make what ufe he 

prefs Catherine invited Mr. Gafcoigne to RufTia, in 1786, pleafes of the defcent of the water, provided that he does not 

to enlarge them to their prefent magnitude. divert the water, at the tail of his eftate, into any other chan- 

On the Dijlribut'ton of the different Falls of Water in Rivers, nel, or that he does not pen up the water higher than the 

— In erecting a mill, care mull be taken to place it fo that level at which it has always entered into his land ; he has alfo a 

it fliall not be impeded by flood-waters, except when they right to infift that the miller below {hall let the water depart 

rife to excefs. When the water below will not run off from his grounds, at the fame level at which it has always been 

freely, but ftands penned up in the wheel-race, fo that the ufed to do. The knowledge of this is very neceflary, be- 

wheel muft work or row in it, the wheel is faid to be tailed', caufe a miller very frequently finds himfelf ferioufly injured, 

or to be in back water or tail water. when he is not entitled to any redrefs. It fcarcely ever 

Upon moil rivers in this country all the falls of water are happens that any confiderable improvements or alteration in 

fully occupied, and at every mill there is a weir, which pens mills can be made, without producing difputes among the 

up the water as high as the mill above can fuffer it to parties interefted. Suppofe, for inftance, that there are 

ftand without inconvenience. Each miller is anxious to ob- two ancient mills upon a river, with an unoccupied defcent 

tain the greateil poffible fall, and he can at any time aug- in running over the lands between them, the proprietor of 

ment the fall, by raifing the furface of his weir ; but as this this land, by deepening the channel and erefting a weir, may 

may produce an inconvenience to the mill above, in prevent- bring all the fall into one place and ereft a mill, without in- 

ing the water from running freely away from its wheel, it fringing the conditions we have laid down ; but ftill the 

is a eonllant fource of difpute and litigation. A mill may miller below him may be confiderably injured : for in the 

be fubjefted to tail-water by the concurrence of fo many original ftate the river, in running down with a regular and 

circumftances, that it is frequently very difficult to know eafy flope, from the upper mill to the lower, held a great 

where to feek the beft remedy, whether the miller ought to quantity of water, which was a corps de referve for the miller 

raife his wheel higher and diminilh his own fall, or infift below, and tended to regulate his fupply. If the upper 

upon a diminution of his neighbour's below him by lowering mill ftopped working, the water contained in the river would 

his weir. ftill run down to him, and fo long as that lafted he could 

The following rule is that which Mr. Smeaton conftantly continue to work, perhaps until the upper mill began to 

followed, in placing fuccelTive dams upon rivers, whether work again, and thus he would fuffer no interruption. The 

for the ereflion of mills or for navigation. In flat countries, eretlion of an intermediate mill cuts off this refource, and 

where the falls of water are fmall, and confequently tail or he will be obliged to ftop working very foon after the new 

back water is moft troublefome, thofe dams mull be fo mill ftops working ; and further, he is obliged to work 

built, that no one fliall pen the water into the wheel-race of when the new mill is at work, or elfe the water poured 

the mill next above it, v^hen the river is in its ordinary fum- down will run over his mill-dam and be wafted ; but, in the 

mer's ftate. The fame rule we have found generally fub- former inftance, the water would have come down lefs fud- 

fifting in ancient mills. denly, and he might be able to fet to work before the whole 

This rule is founded upon reafon ; for if the ereftion of a of the water had efcaped over his weir, 
dam does not afl^eft the mill above by tail-water, in dry fea- In fuch a cafe the lower miUer may be inclined to 

fons, when water is the moft fcarce, it can do no material appeal to the law, but he will find that he has no right to 

injury at any other time. Every mill that is well and pro- prevent his neighbour above from ufing the water in the 

perly conftrufted will clear itfelf of a confiderable depth of fame manner as he does himfelf, and if he finds any altera- 

tail-water, provided it has at the time an increafe of the height tion in his own mill, it is for want of a capacious mill-pond 

of water in the mill-dam or head, and an unlimited quantity to referve the water. In the original ftate the channel of 

of water to draw upon the wheel ; for if floods produce tail- the river in his neighbour's ground above ferved him in fome 

water, they alfo increafe the head water, and afford a fupe- meafure as a mill-dam, by retaining the water for a given time, 

rior quantity to be expended. This is the proper means by though it would not retain it permanently. The advantage 

which a number of mills on the fame river are to be cleared of this he had enjoyed for a long time, when it was no in- 

of back-water, as far as is confident with the mutual enjoy- convenience to his neighbour, but had acquired no right to 



demand that his neighbour's property {hcmld be facrificed 
for his convenience, but he inuft relieve himfelf by making 
an artificial pond for his own mill. 

The fame queftion arifes when any mill is altered or en- 
larged, fo as to confume the water fafter than the river 
brings it down, for fuch a mill can only work for fliort in- 
tervals, and muft then Uop that the water may accumulate 
in the dam until there is a fufficient quantity to fet to work 
again. This is the fyftem of copper-mills and rolling-mills, 
for during the time that the iron or copper is heating in the 
furnace, the mill is (lopped, and^the water gathered in the 
dam ; but when the metal is ready, it is fet to work with all 
the power of the water penned up. This is very prejudicial 
to a mill below, particularly if it is a corn-mill, which can- 
not confume the water fafter than the regular fupply of the 
river, and fometimes alfo to mills above by frequently tailing 
their water. . 

Much ufeful information on thefe points will be found in 
Smeaton's Reports, 3 vols. 4to. 1813. 

We have not, in the preceding article, entered into any 
of the mathematical inveftigations upon the fubjeft of water- 
wheels, becaufe we find few of them founded on experiment ; 
but thofe who wi(h to purfue this fubjeft farther may con- 
fult the following authors, which Dr. Young points out in 
his catalogue. 

KiinftKche abrifs AUerhand, Wafler, Wind-rofs, und 
Hand-muhlen, &c. von Jacob, de Strada a Rolberg, 

'617. , 

Georg Chriftoph Luerner Machina toreutica nova ; Oder 
befchreibung der neu crfundenen Drehmiihlen, 1661. 

Theatrum Machinarum Novum ; das ift, neu vermehrter 
Schauplatz der Mechanifchen Kiinfte, handclt von AUer- 
hand, WafTer, Wind, Rofs, Gewicht, und Hand-muhlen, 
von Geo. And. Bocklern, 1 661. 

Contenta difcurfus mechanici, concementis Defcriptionem 
optimae formea Velorum horizontalium pro ufii Molarum, 
nee non fundamentum inchnatorum Velorum in Navibus, 
habita coram Societate Regia, a R. H. tranflata ex CoUec- 
tionibus Philofophicis M. Dec. num. 3. pa. 61, 1681. 

Dilfertatio hiftorica de Molis, quam praefide Job. Phil. 
Treuer defend. Jo. Tob Miihlberger Ratilbonens Jenae, 

Martin Marten's Wiflcundige befchouwinge der Wind of 
Wadermoolens, vergeleken met die van den heer Johann 
Lulofs Amfterdam, 1 700. 

VoUftandige Miihlen-baukunft, von Leonhard Chriftoph. 
Sturm, 1 7 18. 

Jacob Leopold's Theatrum Machinarum Molinarum, folio, 
1724, 1725. 

Remarquee fur les Aubes ou Palettes des Mouhns, et 
antres Machines mues par le Courant des Rivieres, par M. 
Pilot, Mem. Acad. Roy. Paris, 1729. 

Joh. van Zyl Theatrum Machinarum univcrfale of Groot 
Algemeen, Moolen-bock, &c. Amfterdam, 1734. 

Jo. Caral. Totens. Differ, de Machinis Molaribus optime 
conftruendis, Lugd. Batav. 1734. 

Kurze, aber Deutliche anwcifung zur conftruAion der 
Wind und Wafier-muhlen, von Gottfr. Kindeiling, 1735. 
Defaguliers' Experimental Philofophy, 2 vols. 4to. 1735. 

ArchiteAure Hydraulique, par M. Belidor, 4 vols. 410. 
1737. i75;3. 

Mr. W. Anderfon, F.R.S. Defcription of a Water-wheel 
for Mills. Phil. Tranf. vol. xliv. 1746. 

Leonh. Euleri, De Conftruftione aptiffima Molarum ala- 
tarum difp. Nov. Com. Acad. Pctrop. torn. 4. 1752. 
Memoire dans lequel on dcmontre que I'Eau d'une ChOte, 

deftinee a faire mouvoir quelque Machine, Moulin ou autre 
peut toujours produire beaucoup plus d'efieft en agiflant 
par fon poids qu'en agifs ant par fon choc, et que les roues 
a pots qui tourncnt lentement produifent plus d'effet que 
celles qui tourncnt vite, rclativement aux chutes et aux 
depenfes d'eau, par M. de Parcieux, Acad. Roy. Paris, 


Jo. Albert! Euleri Enodatio queftionis : quo modo vis 
Aquae aliufve fluidi cum maximo lucro ad Molas circuma- 
gendas, aliavc opera perficienda impendi poilit, praemio a 
Societate Regia. Sci. Getting. 1754. 

An experimental Enquiry concerning the Natural Powers 
of Wind and Water to turn Mills and other Machines de- 
pending on Circular Motion, by Mr. J. Smeaton, F.R.S. 
Phil. Tranf. 1759. 

This and Mr. Smeaton's other papers are republifhed with 
his reports, 1813, in 410. 

Memoire dans lequel on prouve que les Aubes de Roues 
Mue3 par les courans des grandes Rivieres feroient beau- 
coup plus d'effet fi elles etoient inclinees aux rayons, qu'elles 
ne font etant appliquees contre les rayons memes, comme 
elles font aux Moulins pendans et aux Mouhns fur Bateaux 
qui font fur les Rivieres de Seine, de Marne, de Loire, &c. 
par M. de Parcieux, Mem. Acad Roy. Paris, 1759. 

Joh Albert Euler's Abhandlung von der bewegung ebener 
Flachen, wenn fie vom Winde Getrieben Werden, 1765. 

Schauplatz des mechanifchen MUhlenbaues, Darinnen von 
Verfchiedenen Hand, Trett, Rofs, Gewicht, WafTer, und 
Wind-miihlen Gehandelt Wird, durch Johann Georg Scopp, 
I.e. iterTheil, 1766. 

Theatrum Machinarum. Molarium, oder fchauplatz der 
Miihlenbaukunft, als der Neunte theil von des fel hrn Jac. 
Leopolds, Theatro Machinarum, von Joh Mathias Beyern, 
1767. 1788. 1802. 

A Memoir concerning the moft advantageous Conftruc- 
tion of Water-wheels, &c. by Mr. Mallet of Geneva. Phil. 
Tranf. 1767. 

Memoire fur les roues HydrauHques, par M. le Chevalier 
de Borda, Mem. Acad. Roy. Paris, 1767. 

Kurzcr unterricht, allerley arten von Wind und WafTer- 
miihlen auf die vortheilhaftefte weife zu erbauen, nebfl eini- 
gen gedanken iibcr die verbelTerung des raderwerks, an den 
miihlen, von Joh Konig, 1767. 

G. G. BifchofT's Beytrage zur Mathefis der Muhlcn, 

Determination generale de I'EfFet des Roues mCies par le 
Choc de I'Eau, par M. I'abbe BofTut, Mem. Acad. Roy. 
Paris, 1769. 

Andreas Kaovenhofer, Deutliche abhandlung von den 
radern der WafTermiihlen, und von dem einrandigen werkc 
der Schneidemiihien, 1770. 

Manuel du Mcuncret du Charpentier des Moulins, redige 
par Edm. Bcquillet, 1775. 

Remarques fur les Moulins et antres Machines, on I'Eau 
tombe en defTus de la Roue, par M. Lambert. 

Experiences et Remarques fur les Moulins que I'Eau 
mcut par en bas dans une Direftion horizontale, par M. 

Remarques fur les Moulins et autres Machines, dont les 
Roues prennant I'Eau "a une certaine Hauteur, par M. 

( The laft three articles are inferted in Mem. Acad. Roy. 
Berlin, 1775.) 

Ausfijhrliche crklarung der Vorfchlage fvir die Langere 
dauer de Mnhlenwerk, nebft ahnlichen gegenftander, in ein 
gefprach vcrfaffet, von Johann Chriftian FuUmann Muhlen- 
meifter, 178c. 



Tratadi) de los Graiios y Modo de Molelos con Economic 
de la Conferva^ion de Attos y de las Harinas ; efcr. en Fr. 
par M. Beguillet, y extraft. v trad, al Caft. con algun 
Notas y un Supplem. por Ph. Marefcaulchi, Madrid, 

Suite de I'Architefture hydraulique, par M. Fabre, 

Memoires fur les Moyens de Perfeftionner les Moulins, et 
la Mouture economique, par C. Bucquet, 1786. 

Manuel ou Vocabulaire des Moulins a Pot, a Amft., 

Die Nothigften KenntnifTe zur Anlegung, Beurtheilung, 
und Berechrung der Waffer-niiihlen, and zwar der Mahl, 
Oehl, und Sage-Muhlen, fiir Anfanger und Liebhaber der 
Miihlenbaukunft, von Joh. Chrill. Huth, 1787. 

An EiTay proving Iron far fuperior to Stone of any Kind 
for breaking and grinding of Corn, &c. by W. Walton, 

Miihlenpraktik, oder unterrichtin dem Mahlen der Brod- 
friichte, fiir Polizeybeamtc, Gaverkfleute und Haufwirthe, 
von L. Ph. Hahn, 1790. 

The young Mill-wright and Miller's Guide, by Oliver 
Evans, Philadelphia, 1790. 

Manuel du Meunier, et du Conftrufteur des Moulins a 
Eau et a Grains, par C. Bucquet, 1791. 

Praktifche anweifung zum Miihlenbau, von. Lr. Claufen, 

Befchreibung zweir Machinen zur Reinigung des Korns, 
von Lr. Clauferl, 1792. 

Inftrudtions fur I'Ufage des Moulins "a Bras, inventes et 
Perfeftionnes par les Citoyens Durand, P^re et Fils, Me- 
chaniciens, 1793. 

Theoretifch-praktifche abhandlung liber die Befferung 
der Muhlrader, von dem VerfalTer der Zweckmaffigen, 
Luftreiniger, &c. 1795. 

A Treatife on Mills, in four Parts, by John Banks, 

Handbuch der Mafchinenlehre, fur prakiker und aka- 
demifche lehrer, von Karl Chriftian Langfdorf, 1797. 


On the Power of Machines ; including Barker's Mill, 
Weftgarth's Engine, Cooper's Mill, horizontal Water- 
Wheel, &c. by John Banks, 1803. 

The experienced Mill-wright, by Andrew Gray, mill- 
wright, 1804. 

The Tranfadlions of the Society of Arts and Manufac- 
tures ; feveral of the volumes of which contain improve- 
ments in Mill-work. See alfo the Repertory of Arts, firft 
feries 16 volumes, and fecond feries 31 volumes. 

Hachette, Traite Elementaire des Machines, 4to. Paris, 

Buchanan's Effays on Millwork, 181 1, Svo. 

Water, Column of, fignifies fo much of the mafs of 
water which is contained in a pipe, or any other veffel, as 
prefles againft any plane furface ; which furface is called the 
bafe of the column. 

All columns of water are confidered as if they were ver- 
tical prifms, of the fame fize and figure as the bafe, /'. e. the 
furface upon which they prefs, and as high as the greateft 
height to which the water rifes in the pipe or other 

This is demonftrable in hydroftatics, (fee Fluid, ) and alfo 
that fluids prefs equally in all direftions, fo that the preffure 
againft a vertical or inclined plane is the fame as againft an ho- 
rizontal plane, provided that the planes are of the fame extent. 

and that the water which preffes upon them rifes to an equal 
height above them. This will be true whether tlie fize of 
the veffel which contains the water is greater or lefs than 
the furface upon wliich the preffure is exerted ; the preffure 
will be neither more nor lefs than the weight of a perpen- 
dicular column or prifm of water, having a horizontal bafe, 
equal and fimilar to the plane or bafe upon which the pref- 
fure is exerted ; and an altitude equal to the level of the 
furface of the water above the bafe. 

Rule tojind the Prejfure or Wtight of any Column of Water 
in Pounds Avoirdupois. — If the bafe of the column is of a 
circular figure, fuch as tlie pillon of a pump, take the dia- 
meter in inches, and alfo the perpendicular height of the 
furface of the water above the bafe of the column in feet ; 
then fquare the diameter in inches, to obtain the area of the 
bafe in circular inches, and multiply this by the decimal .341 
o"" by •34> t^^'s gives the weight of one foot in height of the 
column ; lailly, multiply by the number of feet in the alti- 
tude of the column, and the refult is the weight of the whole 
column of water in pounds avoirdupois, or, what is equiva- 
lent, the preffure exerted by the water upon the bafe or plane 
againft which it afts. 

If the bafe of the column is fquare or reftangular, it will 
be more convenient to find its area in fquare inches, and then 
the conftant decimal is .434. 

The reafon of thcfe rules is, that a cylindrical column of 
rain-water, of i inch in diameter and i foot high, weighs 
.3408853 lbs. avoirdupois ; and a fquare prifm, I inch 
fquare, and i foot high, weighs .4340277 lbs. avoirdupois ; 
the other multiphcations are only to find liow many of fuch 
cyhnders or prifms are contained in the whole column. 

Example I. — It is required to find the weight which bears 
upon the pifton or bucket of a pump, whofe barrel is 9 
inches diameter withinGde, and the height of the furface of 
the water above the pifton 67 feet. Diameter 9 x 9 = 81 
circular inches of area x .341 lbs. = 27.62lbs., which is the 
weight of every foot in height x 67 feet = 1850.54 lbs. 
which is the weight that bears upon the pifton, and which 
muft be overcome to draw it up. 

Example 2. — It is required to find the weight which bears 
upon a reftangular valve, which is 7 inches by 5 inches, 
and the water rifes 67 feet above it. 7 x 5 = 35 fquare 
inches of furface x .434 lbs. = 15.2 lbs. for every foot of 
altitude X 67 feet = 1018 lbs.; the weight refting upon the 

Note — In pumps it generally happens that there is a 
column of water contained in the pipe, beneath the pifton 
or valve, and is fufpended therefrom, becaufe the preffure 
of the atmofphere is taken off from fuch column by the 
valve or pifton, and the preffure of the atmofphere upon the 
furrounding water forces the water up the pipe until it 
touches the pifton, provided the height is not more than 
33 feet. In all fuch cafes, the height of the column de- 
pending beneath the valve or pifton muft be added to the 
height of the column above the pifton, becaufe it is fo much 
additional burthen or preffure. 

Rule tojind the Prejfure luhich any Column of Water exerts 
upon each fquare Inch or circular Inch of its Bafe, in Poundi 
Avoirdupois. — Multiply the height of the column in feet by 
.434, for the preffure on each fquare inch of the bafe, or 
by .34 lbs. for each circular inch. 

In large works it is more convenient to take the area of 
the bafe in fquare feet, in which cafe the multiplier will be 
62.5 lbs. ; or, if it is circular feet, 49,0875 lbs. 

Example — A tank to contain water, ten feet deep, is 
lined with vertical walls of mafonry, each ftone of which is 
oue foot fquare in its vertical face ; required the preffure 



which will be exerted upon each ilone of the mafonry to 
thruft it outwards. 

Depili l)en<>aili I'reffure on Mcli St -ne, 

the Surface or on every fijiiare Foot, 
in Fen. in !'• umis. 

1 61.5 

2 125 

3 187.5 

4 250 

5 312-5 

6 375- 

7 437-5 

8 ■ 500 

9 562-5 
10 625. 

The length and width of the tank does not influence the 
preffure upon each Hone ; becaufe, following oui- firft pro- 
pofition, we are only to regard the magnitude of the plane 
againft which the water ads, and the depth at which it is 
fituated beneath the furface. But in all cafes when the 
plain is not horizontal, the depth of the water will be greater 
upon fome parts of the plane than upon others. The 
depths mud therefore be taken from the centre of prejfure of 
the plane ; fee that article in Vol. VII. 

The knowledge of the centre of preffure is required, in 
order to apply this calculation to wooden velTels, fuch as the 
large backs ufed by brewers ; or to find the prefTure againft 
the gates of a fluice or lock, or in any other cafe where the 
wood planks, or the ftones of the mafonry are fo united to- 
gether into one mafs, that the whole fide of the vefl"el muit 
be removed together. If the plane againft which the water 
ads rifes up as high as the furface of the water, and is of a 
reftangular figure ; that is, if all its horizontal dinienfions, 
whether taken at the bottom of the veflel or at the top, are 
equal, then the centre of prefTure is fituated at jds of the 
greateft depth beneath the furface. 

Example. — A wooden vat is 18 feet long, and contains 
water 6 feet deep ; required the force which the water ex- 
erts againft the fide of the vat to force it outwards. Two- 
thirds of 6 feet is 4 feet, which is the depth of the centre of 
prefTure: 4 x 62. 5 = 250 lbs. is the mean prelTure upon 
each fquare foot of t lie plane, 18 feet long x 6 feet deep 
— 108 fquare feet of area x 250 lbs. 27,000 lbs., which is 
the force exerted againft the fide of the veffel, and niuft be 
refifted by the ttrength of the materials. 

On the Means of meafuring or guaging the Quantity of run- 
ning JVater The ancients feem to have had no other mea- 

fure of running water than that uncertain and fallacious one, 
which depended wholly on the perpendicular feftion of a 
ftream, without confidcring the velocity of the motion. The 
firft wiio opened a way to the truth was Benedift Caftelli, 
an Italian, and friend of Galileo. He firft (hewed that the 
quantity of water, flowing through a given feftion of a ftream, 
is proportional to the celerity with which the water is carried 
through that fedion. This obfcrvation engaged philofo- 
phers to ftudy the doftrine of the motion of fluids with 
much diligence, and after Caftelli's time there was fcarcely 
any mathematicians who did not endeavour to add fomething 
thereto, either by experiments or by reafoning and argu- 

But few of them, until the illuftrious fir Ifaac Newton, 
had any fuccefs, becaufe of the exceeding difficulty of the 

Thofe who ftudicd the theory laid down fuch theorems as 
were found to be falfe, when brought to the tcft of experi- 
ments, and thofe who laboured in making experiments fre- 
quently otpitted to obferve fome minute circumftances, tlic 

importance of which they had not yet perceived. Hence 
they differed greatly from one another, and almoft all of 
them erred from the teal meafure. 

The theory of hydrauhcs has never been carried to a very 
high degree of perfeftion upon mathematical foundation 
alone, nor has it hitherto, even with the affiftance of experi- 
ment, been rendered of much praftical utility. Newton 
began the invelligation of the motions of fluids on true 
principles. Daniel BernouiUi added much valuable matter 
to Newton's propofitions, both from calculation and expe- 
riment. D'Alembert, and many later autliors, have exer- 
cifed their analytical talents in inquiries of a fimilar nature. 

Dr. Robifon obferves that thefe, and other mathema- 
ticians of the firft order, feem to have contented themfelves 
with fuch views as allowed them to entertain themfelves with 
elegant applications of calculus. They rarely had any op- 
portunity of doing more, for want of a knowledge of fafts, 
but they have made excellent ufe of the few which have 
been given them. 

It requires much labour, great variety of opportunities, 
and great expence, to learn the multiplicity of things which 
are combined, even in the fimpleft cafes of water in motion. 
Thefe advantages feldom fall to the lot of a mathema- 
tician, and he is without blame when he enjoys the pleafures 
within his reach, and cultivates the fcience of geometry in 
its moft abftrafted form. Here he makes a progrefs which 
is the boaft of human reafon, being almoft infured from 
every error, by the iulclleitual fimplicity of his fubjeft. 
But were wc to turn our attention to material objedls, we 
know neither the fize and fhape of the elementary particles 
of water, nor the laws which nature has prefcribed for their 
aftion. We cannot, therefore, prefume to forefec their 
effeds, calculate their exertions, or direcl their aftions, with 
any reafonable expeftations of certainty. 

A different and more praftical mode of attaining hy- 
draulic knowledge, has been attempted by a dillinft clafs 
of inveftigators. Thefe have begun from experiment alone, 
and have laborioufly deduced, from very ample obfervations 
of the aftual refults of various particular cafes, the general 
laws by which the phenomena appear to be regulated, or 
at leaft the formulas by which the cffeft of new combina- 
tions may be predifted. But it muft be confefTed, that 
thefe formulas, however accurate, are almoft too intricate 
to be retained in the memory, or to be very cafily applied to 
calculations from particular data. 

There are two gentlemen whofe labours in this refpeft 
deferve very particular notice, profiflor Michelotti, at Tu- 
rin, and abbe Boffut, at Paris. The firft made a pro- 
digious number of experiments, both on the motion of 
water through pipes and in open canals. Tlie experi- 
ments of Boffut are alfo of both kinds, and though on 
a much fmaller fcale than thofe of Michelotti, they feem 
to deferve equal confidence. The chevalier de Buat, who 
has taken up this matter where the abbe BoflTut left it, 
has profecuted his experiments with great afllduity and fin- 
gular fuccefs. 

Mr. Eytelwein, a gentleman honoured with feveral em- 
ployments and titles relative to the public architefture of 
the Pruflian dominions, made a tranflation of Buat's works 
into German, with important additions of his own -, and he 
alfo publifhed " Handbuch der Mechanik und der Hydrau- 
lik," Berlin, 1801. In this compendium of mechanics and 
hydraulics, he has coUcfted the principal fafts that have 
been afcertained, as well by his own experiments as by thofe 
of former authors, efpecially fuch as are the moft capable 
of practical application. He appears to have done this in 
fo judicious a manner, as to make his book a moft valuable 



abllradl; of every tiling that can be deduced from theory, pendicular line. Goofeberries are very nearly the weight of 
refpefting natural and artificial hydraulics. The elegant con- water, and may be employed fingly, to fhew its velocity at 
cifenefs of his manner deferves fo much the more praife, as different depths. 

bis countrymen too often make a merit of prolixity. Example. — A canal meafured eight feet in width, and 

In our article Discharge, ws have given the general four feet in depth, the fides being perpendicular ; then the 
principles of the motion of fpouting fluids ; and under River area of the feftion is thirty-two fquare feet. It was found 
the theory of water running in rivers. The objeft of the by experiments with three apples, that the current ran 
prefent article v/ill be to lay down fuch rules as may be im- through a fpace of fifteen feet in five feconds, in another 
mediately applicable to the ufe of the engineer. experiment fix feconds, and in a third four feconds and a half. 

In all cafes of gauging flreams, the quantity which flows. What is the quantity of water paffing through this canal ? 
in any given time, is obtained by meafuring the area of the The mean of all thefe is five feconds and one-fixth 
aperture, or channel, through which the water flows, and during which the water moved fifteen feet. Now as five 
finding the velocity with which the water moves through feconds and one-fixth is to fifteen feet, fo is fixty feconds to 
that aperture. To find the area of the aperture is a fimple a hundred and feventy-four feet, which the fl^reara flows in 
operation of menfuration, but to afcertain the velocity is not the fpace of a minute. Then thirty -two fquare feet (the 
fo eafy. There are two different methods of determining area), multiplied by 174 feet, gives 5568 cubic feet which 
the velocity. The firft is, by obferving the rate of motion ia the quantity of water flowing through the canal every 
of the furface, either by means of fmall light bodies thrown minute. 

into the ftream, or by employing inftruments adapted to This is the method recommended by Defaguliers, and 
meatire the rate at which the ftream moves. This method if carefully executed, and the trials frequently repeated 
is only appUcable in cafes of open canals and rivers, where is tolerably exaft. Several authors have fuppofed this 
the water flows with a flow motion. The other method is method might be much improved, by employing fome in- 
more general, and is applicable to the greateft velocities ; ftrument to fliew the velocity of the ftream by infpeftion. 
becaufe it is derived from calculation, according to the depth There are many ingenious inventions for this purpofe. 
of water, or height of column, which urgei the flowing Stream- Meafurers. — M. Pilot invented a ftream -meafurer 
water, and occafions its motion. of a fimple conftruAion, to find the velocity of any part 

To mcafure the Quantity of Water running In a River or Ca- of a ftream. This inftrument is compofcd of two loiig 
nal, Firft Method — Choofe a part of the channel where the tubes of glafs open at both ends, and placed in a perpen- 
banks are of a determinate figure, and where they continue dicular direftion in the ftream of water : one of thefe 
of the fame breadth and depth for a length of ten, twenty, tubes is cylindrical throughout and ftraight ; but the 
or thirty feet, the longer the better, and the more regular other has its loweft extremity bent nearly at right angles 
the banks are, the better the obfervations will be. Meafure fo as to form a horizontal branch, which gradually en- 
the breadth and the depth, or other dimenfions which may larges like a funnel, or the mouth of a trumpet ; both 
be necelFary, to find the area, or feftion of the paffage, thefe tubes are fixed to the fide of a triangular prifm of 
through which the water flows. Take thefe meafures at wood, with the lengths of the tubes parallel to the length 
feveral different points, and if there is any difference at dif- of the prifm, and their lower extremities both on the fame 
ferent places, find the area at each place, and take a mean level ; the horizontal branch of the tube is carried through 
between them. the prifm, fo that the end of the trumpet-mouth opens in 

Then proceed to find the velocity of the motion, by one of the angles of the prifm. The upright parts of the 
throwing in a cork, or other light body, and obferving, by tubes ftand one befide the other, and are let into grooves 
a ftop-watch, or pendulum, what number of feconds it takes in the prifm, fo as to be tolerably well preferved from ac- 
to flow through a given length of the channel ; for in- cidents. The face of the prifm in which thef* tubes 
ftance, the length of ten, twenty, or fifty feet, which was ftand, is graduated on the edges clofe by the fides of 
chofen in the firft inflance for the experiment, and marked them into divifions of inches and lines, 
oijt by ftretching two ftrings, parallel acrofs the river. This To ufe this inftrument, it is placed perpendicularly in 
trial muft be repeated feveral times, and as the inftant when the water in fuch a manner, that the opening of the trum- 
the floating body arrives at the laft firing, can be very pet-mouth at the bottom of one of the tubes, ftiall be com- 
exaftly noted, this method admits of confiderable exaftnefs. pletely oppofed to the direftion of the current, in order 
A mean of the different refults muft be taken for the true that the water may pafs freely through the funnel up into the 
velocity. perpendicular tube. Then by obferving to what height the 

It is true that this only gives the velocity of the water water rifes in each tube, it will be found to rife higher in 
at the furface, and the water moves with different velo- the tube with the trumpet-mouth than the other, and the 
cities at different depths, beneath the furface ; (inftead of quantity of this difference will be the height due to the ve- 
a fingle light body to float upon the furface of the water), locity of the ftream 

we are recommended to employ a cylindrical rod of wood, 
of a length fomcthing lefs than the depth of the water : 
this is to be ballafted by a weight at the lower end, fo 
that it will fwim juft upright in ilanding water, and with 

It is manifeft that the water will rife in the ftraight cy- 
lindrical tube to the fame height as the furface of the ftream : 
this is by the hydroftatic preffure. But the water of the 
current entering by the funnel into the other tube, will be 

the upper end of the ftick about an inch above water. By compelled to rife above that furface to fome certain height, 

ufing this, inftead of a fingle cork, we are fuppofed to attain at which height it will be fuftained by the impulfe of the 

the mean velocity of the ftream at its different depths, inftead moving fluid; that is, the momentum or impulfe of the 

of the velocity of the furface. ftream will be in equilibrio with the column of water fuf- 

Inftead of a cyhnder of wood, three or four apples, tained in one tube above the furface of that in the other, 

ftrung together by a ftring, will anfwer the purpofe very In eftimating the velocity by means of this inftrument, wc 

well, the lower ones being loaded by putting nails in muft have recourfe to the following rules : if the height of 

them till they are rather heavier than water, fo that the the column fuftained by the ftream, or the differenc* of 

apples, when put into ftanding water, will hang in a per- heights in the two tubes be taken in feet, the velocity of 

Vol. XXXVIII. O the 


the ftream^rt-recond in feet will be 6.5 times the fquare root 
of the height. ■ 1 • • 

If the height be meafured in inches, then the velocity in 
feet per fccond will be 1.88 times the fquare root of the 
height, nearly. It will be eafy to put the funnel into the 
moft rapid part of the ftream, by moving it about to different 
places, until the difference of altitude in the two tubes be- 
comes the greatefl. In fome cafes, it will happen that the 
immerfion of the inftrument will produce a little eddy in the 
water, and thus difturb the accuracy of the obfervation ; 
but keeping the inflrument immerfed only a few feconds 
will correa this. The wind alfo would affeft the accuracy 
of the experiments ; it is therefore advifeable to make them 
when there is Uttle or no wind. 

By means of this inftrument, the velocity of water at va- 
rious depths in a canal or river may be found with tolerable 
accuracy, and a mean of the whole drawn. Where great 
accuracy is not required, the bent tube with the funnel at 
bottom will alone be fufficient, becaufe the furface of the 
water will be indicated with tolerable precifion, by that 
part of the prifmatic frame for the tube which has been 
moiflened by the immerfion. ., . „ n. u 

M. Pilot likewife propofed that a fimilar inftrument fhouid 
be ufed inftead of a log, to determine the rate at which a 
fhip fails. For this purpofe, in the middle of a vefTel, or as 
near as can be to the centre of its ofcillations, place two 
tubes of metal of three or four lines in diameter, one of 
them being ftraight, and the other bent at bottom and 
enlarged into a conical funnel. The lower ends of both 
are to dip into the water in which the veffel fails, and 
there will be no evil to apprehend from orifices fo minute. 
Into thefe metalhc tubes, two others are clofely fitted at 
a convenient height for the obfervations. The water will 
rife, in the firft of thefe tubes, up to its level on the outfide 
of the (hip ; and in the fecond, up to a certain height, which 
will indicate as above the velocity of the veffel. For the 
funnel being turned towards the prow of the fhip, it will, in 
confequence of the motion, be affefted in like manner, as 
if it were plunged into the ftream of a running water. The 
aftual velocity of the veftel is found by the fame rules as 
that of the current. This method has been repropofed in 
this country, without any acknowledgments to M. Pitot. 
We do not, however, recommend its adoption on board a 
(hip ; for, notwithftanding its theoretical ingenuity, it is liable 
to many fources of error in praftice, and would not, it is 
probable, furnifh more accurate meafures of a fhip's way, 
than thofe deduced from the common log. 

In the praAical ufe of M. Pilot's inftrument, a great 
difficulty is experienced from the ofcillations of the water 
in the tubes, which it is not eafy to prevent, and a mean 
height of the ofcillating water muft be taken. 

M. Du Buat made trials of the inftrument, and found it 
could not be trufted for any other purpofes than to give the 
ratios of different velocities. He found the inftrument was 
better without the ftraight tube, and he employed only one 
tube with its lower end turned horizontally, in the direc- 
tion of the ftream, it was made of tinned plate inftead of 
glafs, and fufficiently large to admit a float to fhew the 
height of the water in the tube. Inflead of making the end 
of the tube an open trumpet-mouth, he ufed to clofe it by 
a flat plate, with a fmall perforation in the centre to admit 
the water through it, or in fome cafes feveral fmall perfora- 
tions. In this way, the water will rife in the tube, juft the 
fame as if it was open ; but the ofcillations of the column 
will be avoided, or greatly diminifhed. 

The hydraulic quadrant has been recommended by feve- 
ral authors, for mcafuring the velocity of water. 

It confifts of a fmall quadrant with a divided arch, and 
having two threads moving round its centre. One of thefe 
is fhort, and carries a plummet which always hangs in air, 
and ferves to place the quadrant in its true polltion. The 
other thread is longer, and carries a weight whofe fpecilic 
gravity is greater than that of water, and which plunges 
more or lefs deep in the current as the thread is lengthened. 
The inftrument is held over the water, fo that the plummet 
of the long thread hangs in the water, and the force of the 
current will remove it from the perpendicular, whilft the an- 
gular diftance from the other thread, which is a vertical 
Une can be afcertained by the divifions on the arch of the 
quadrant ; the quantity of this deviation from the perpendi- 
cular is the meafure of the force, and confequently of the 
velocity of the current. BofTut has fhewn, that the force 
of the current is as the tangent of the angle which one 
thread makes with the other, and gives direftions for ufing 
this inftrument to try a current at different depths. 

Dr. Brewfter, in his edition of Fergufon's leAures, re- 
commends a fmall and light wheel, hke an underfhot water- 
wheel, with float-boards on its circumference. It is provided 
with an apparatus to afcerlain and record the number of 
turns it makes, and is held in the ftream, fo that the water 
may aft upon the float -boards to turn it round ; and from the 
number of turns it makes in any given time, the velocity 
of the ftream may be computed. He direfts the wheel 
to be made of the lighteft materials, and about ten or 
twelve inches in diameter : it is fumifhed with four- 
teen or fixteen float-boards. The centre of the wheel is 
perforated with a hole, and tapped to receive a delicate 
fcrew or wire, which forms the axis upon which it re- 
volves, with as little friftion as poflible. At each end 
of the fcrew or axis, is a handle to hold it by, and to fup- 
port the wheel ; and to one of thefe handles an index is 
fixed, pointing to divifions on the circumference of the 
wheel, which coniift of 100 parts. This index (hews 
the aliquot parts of a revolution, whilft the number of 
threads which the wheel advances on the fcrew fhews the 
number of whole turns it makes. 

To prepare this inftrument for ufe, the wheel muft be 
turned round upon the fcrew until it arrives quite at one end 
of it, and till the index points to zero of the divifions on the 
rim of the wheel ; then hold the axis or fcrew horizontally 
by the two handles, fo that the floats dip in the water and 
turn the wheel round upon the fcrew. 

By means of a ftop-watch, or a pendulum, find how 
many revolutions of the wheel are performed in a given 
time, a minute, for inftance. Multiply the mean cir- 
cumference of the wheel, /. e. the circumference deduced 
from the mean radius, meafured from the centre of im- 
pullion upon the float-boards to the centre of the wheel, 
by the number of revolutions, and the produft will be the 
number of feet which the water moves through in the given 
time. On account of the friftion of the fcrew, the refift- 
ance of the air, and the weight of the wheel, its circum- 
ference, will move with a velocity a little lefs than that of 
the ftream ; but the diminution arifing from thefe caufes, 
may be eftimated with fufficient precifion for all the pur- 
pofes of the praftical mechanic. 

This, we think, is one of the beft ftream-meafurcrs, becaufe 
it will give a correft meafure of the motion at the furface 
of the water ; but it will not give the velocities at the dif- 
ferent deptlis beneath the furface, nor do we know any 
machine which will efieftually anfwer that purpofe. 

By means of this inftrument, we can obtain the velocity 
of the furface with greater accuracy than perhaps by any 
other means ; but to afcertain the quantity of water which 



fhallbe difcharged, we mull know the mean velocity of the 

Ral'io between the mean Velocity of running Water and the 
Velocity of the Top and Bottom of a ChanneK — M. Du Buat 
ftates, that the fuperficial velocity of a (h-eam of water 
always bears a certain relation to the mean velocity, fo that 
we can derive one from the other by an arithmetical rule. 

From a great number of experiments, he difcovered the 
following laws : ill. That the velocity at the furface in the 
middle of the ilream, (in flow motions,) is to the velocity at 
the bottom of the ilream, in a ratio of confiderable inequa- 
lity. 2d, This ratio diminifhes as the velocity increafes, and 
in very great velocities approaches to the ratio of equality. 
3d, What was mod remarkable, was, that neither the mag- 
nitude of the channel, nor its flope, had any influence in 
changing this proportion, whilft the mean velocity remained 
the fame. Whether the ftream ran in a channel with the 
bottom covered with pebbles, or coarfe fand, the propor- 
tions between the two velocities was, as nearly as poffible, 
the fame as when it ran in a fmooth channel. 4th, If the 
velocity at the furface in the middle of the ftream be con- 
(tant, the velocity at the bottom will be alfo conftant, and 
will not be affefted by the depth of water or magnitude of 
the ftream. In fonie experiments, the depth was thrice the 
width, and in others the width was thrice the depth. This 
changed the proportion of the magnitude of the feftion, 
to the magnitude of the rubbing part, but made no change 
in the ratio between the velocities at the top and bottom. 

The place of the mean velocity in the fedlion of the 
ftream could not be difcovered with any precifion. In 
moderate velocities, it \Vas not more than one-fourth or one- 
fifth of the depth diftant from the bottom. In very great 
velocities, it was fenfibly higher, but never in the middle of 
the depth. 

In all cafes he computed the mean velocity by meafur- 
ing the quantities of water difcharged in a given time. His 
method of meafuring the bottom velocity was fimple, and 
probably juft ; he threw in a goofeberry, as nearly as polfible 
of the fame fpecific gravity with the water ; it was carried 
along the bottom without touching it. We have already ob- 
ferved, that the ratio between the velocity at the furface in 
the middle, and the velocity at the bottom, diminiflied as the 
mean velocity was increafed. This variation he was enabled 
to exprefs in a very fimple manner, fo as to be eafily re- 
membered, and to enable us to find any one of them from 
having obferved another. 

Dr. Robifon ftates, that if we take unity from the fquare 
root of the fuperficial velocity, in the middle of the ftream, 
exprefled in inches ^frfecond, the fquare of the remainder is 
the velocity at the bottom ; and the mean velocity is the 
half fum of thefe two. Thus, if the velocity of the furface 
in the middle of the ftream be twenty-five inches per fecond, 
its fquare root is five ; from which if we take unity, there 
remains four. The fquare of this, or 16, is the velocity 

at the bottom, and — , or 20^, is the mean velocity. 

This is a very curious and moft ufeful piece of inform- 
ation. The velocity of the furface in the middle of the 
ftream, is the eafieft meafured of all, by any light fmall body 
floating down it, or by a ftream-meafurer ; and the mean 
velocity is the one which regulates the difcharge, and all 
the moft important confequences. 

Dr. Robifon gives the following table of thefe three 
velocities, which will fave the trouble of calculation in fome 
of the moft frequent queftions of hydraulics. 


y ill Indies/ 

er Second. 


y in Inches per Second. 















1. 08 1 




































































































































































































































































































The knowledge of the velocity at the bottom is of ufe to 
an engineer, to enable him to judge of the aftion of a 'ftream 
on its bed. Every kind of foil will bear a certain velocity 
without changing the form of the channel. A greater velo- 
city would enable the water to tear it up, and a fmaller ve- 
locity would permit the depofition of more moveable mate- 
O 2 rials 


rials from above. It is not enough, then, for the perma- 
nency of a river, that the accelerating forces are fo adjufted 
to the fizc and figure of its channel, that the current may ac- 
quire an uniform velocity, and ceafe to accelerate. It muft 
alfo be in equilibrio with the tenacity of the channel. 

It appears from obfervation, that a velocity of three 
inches fer fecond at the bottom, will juft begin to work upon 
fine clay fit for potter)-, and however firm and compaft it may 
be, it will tear it up. Yet no beds are more liable than 
clav, when the velocities do not exceed this, for the water 
• foo'n takes away the impalpable particles of the fuperficial 
clay, leaving the particles of fand (licking by their lower 
half in the reft of the clay, which they now protect, making 
a very permanent bottom, if the llream docs not bring down 
gravel or coarfe fand, which will rub off this very thin 
cxuft, and allow another layer to be worn off. A velocity 
of fix inches per fecond, will lift fine fand ; eight inches will 
lift fand as coarfe as linfeed ; twelve inches will fwcep along 
fine gravel; twenty-four inches will roll along rounded 
pebbles an inch in diameter ; and it requires three feet per 
fecond at the bottom to fweep along (hivered angular ftones 
of the fize of an egg. 

Dr. Young gives an excellent fimple rule for the fame ob- 
jeA, which is only a trifle different from Dr. Robifon's ; he 
tlates, that from a mean of all the bed experiments, he found 
that, if the fquare root of the mean velocity of any ftream 
(running in an uniform open channel) be added to fuch mean 
velocity, it will give the fuperficial or top velocity in the 
middle ; or if dedufted therefrom, it will leave the bottom 
Telocity : whence we have deduced the follow|ing praAical 
rule, 1)12. 

1. Having found the top velocity, expreffed in any con- 
venient meafure, which will corrcfpond with the refult 

To find the bottom velocity, add the conflant number .25 
(or \') to the top velocity ; cxtradl the fquare root of the 
fum, and double it ; again add I to the top velocity, and 
from the fum deduft the double root before found : the re- 
mainder is the bottom velocity of the ftream. 

2. To find the mean velocity from the top velocity, add 
the conftant number .5, (or \) to the top velocity, and from 
their fum deduft the fquare root found in the firft rule : 
the remainder is the mean velocity. 

Or, 3. To find the mean velocity from the bottom velo- 
city, add the conftant number .25, (or^J) to the bottom ve- 
locity, and extraft the fquare root of the fum ; then to this 
fqiare root add the bottom velocity, and the conftant num- 
ber, .5, and their fum is the mean velocity. 

Theft are true in all cafes, provided the top and bottom 
velocities are related to each other, as Dr. Young ftates. 
For example, Mr. Watt obferved the furface of the water 
in an open canal to move with a velocity of 17 inches /cr fe- 
cond : What was the bottom velocity ? 

By our firft rule 17 -|- .25= 17.25, of which extraft the 
fquare root; it is 4.15; twice this is 8.3. Again, to 
the top velocity 17 add i = 18, and deduft 8.3, it leaves 
9.7 for the bottom velocity. Mr. Watt obferved the bot- 
tom velocity to be JO inches per fecond. 

2. To find the mean velocity, add .5 to the top velocity 
17, it gives 17.5; deduft 4.18, and we get 13.32 inches 

per fecond for the mean velocity. 

3. If we take Mr. Watt's obfervation of the bottom ve- 
locity of I o inches per fecond, inftead of the top ; then to 
Jind the mean velocity 10 -|- .25= 10.25, of which the fquare 
root is 3.201 ; and 10 -| .5 = 10.5 ; add thefe together, 
ihns (3.201 -)- 10.5) = 13.701 inches per fecond for the 

mean velocity ; which only exceeds that deduced from t^•<.* 
top velocity by little more than jd of an inch in a 

By the aid of this rule, and the wheel ftream-meafurer 
before defcribed, great accuracy may be obtained. Care 
muft betaken to apply the wheel in the centre of the llrcam, 
on the furface, or rather at that place where the velocity of 
the furface is found to be the greateft. 

Second Method of meafurmg the Flowing of Water in an 
open Canal. — When a river flows with an uniform motion, 
and is neither accelerated nor retarded by the aftion of 
gravitation, it is obvious that the whole weight of the water 
muft be employed in overcoming the friftion of the water 
againft the bottom and fides. 

The principal part of this friftion is as the fquare of 
the velocity, and the friftion is nearly the fame at all depths : 
for profeffor Robifon found, that the flow of the fluid 
through a bent tube was not increafed by increafing the 
prcffure againft the fides, being nearly the fame when tlie 
bended part of the tube was fituated horizontally, as when 
vertically, the fame difference of level being preferved. 

The quantity of friftion will, however, vary, according 
to the furface of the fluid which is in contaft with the folid, 
in proportion to the whole quantity of fluid ; that is, the 
friftion for any given quantity of water will be, as the fur- 
face of the bottom and fides of a river direftly, and as the 
whole quantity of water in the river inverfely; thus, fup- 
pofing the whole quantity of water to be fpread on a hori- 
zontal furface equal to the bottom and fides of the river, 
the friftion is inverfely as the depth at which the river 
would then ftand. This is called the hydraulic mean 

If the inclination or flope of the furface of water in a 
river varies, the defcending weight, or the force that urges 
the particles down the inclined plane, will vary as the 
height of the fall in a given diftance ; confequently, the 
friftion, which is equal to the defcending weight, muft 
vary as the fall ; and the velocity being as the fquare root 
of the friftion, muft alfo be as the fquare root of the fall. 
Suppofing the hydraulic mean depth to be increafed or 
diminiftied, the inclination remaining the fame, the friftion 
would be diminiftied or increafed in the fame ratio ; and, 
therefore, in order to preferve its equality with the defcend- 
ing weight, the friftion muft be increafed or diminiftied, by 
increafing the velocity in the ratio of its fquare to the 
hydraulic mean depth ; that is, increafing the velocity in the 
ratio of the fquare root of the hydraulic mean deptli. 

Mr. Eyteltvein's Rule is, that the velocity of a ftream will 
be in the joint proportion of the fquare root of the hydrauhc 
mean depth, and the fquare root of the fall in a given diftance ; 
or as a mean proportional between thefe two quantities. 

Taking two Enghfti miles for a given length upon a 
ftream, we muft find a mean proportional between its hy- 
drauhc mean depth and its fall in two miles in inches, and 
inquire what relation this bears to the velocity in a par- 
ticular cafe. We may thence expeft to determine it in any 
other. According to Mr. Eytelwein's formula, this mean 
proportional is +;ths of the velocity in a fecond in inches. 

In order to examine the accuracy of this rule, we may 
take an example, which could not have been known to Mr. 
Ey telwein. Mr. Watt obferved, that in a canal 1 8 feet wide 
above, and 7 below, and 4 feet deep, having a fall of 4 inches 
in a mile, the velocity was 17 inches ^r fecond at the fur- 
face, 14 in the middle, and 10 at the bottom. The mean 
velocity may be called 13 J inches, in a fecond. Now to 
find the hydraulic mean depth, we muft divide the area of 



the feftion ( ? x 4) = 50 fquare feet, by the breadth 

of the bottom and length of the Hoping fides added toge- 


whence we have — — -, or 20. i« inches : and the fall 
20.6 ^ ^ 

degrees of preffure ; and found that the friftion could not 
be reprefented by any fingle power of the velocity, although 
it frequently approached to the proportion of that power 
of the velocity, of which the exponent is 1.8 ; but that it ap- 
peared to confift of two parts, the one varying fiaiply as the 
velocity, the other as its fquare. The proportion of thefe 
parts to each other muft, however, be confidered as dif- 
ferent, in pipes of different diameters ; the firft part being 
lefs perceptible in very large pipes, or in rivers, but be- 

:nes tor tne velocity, wtucn is conliaerably leis accurate. f °™"S Sf^'Jf ^l'^" ^^^ ^^"""'^ '" T^''^ "^T^^ '"^' ' .''''''''^ 
For another example we may take the river Po, which t"*^ ''^™nd alfo becomes greater, for each given portion of 
Is one foot in two miles, where its mean depth is 29 feet, "i^Jj "*" °^ '^^ P'P''' ^' '^*^ diameter is dimi- 

If, with Dr. Young, we exprefs all the meafures in 
Englirti inches, calhrig the height employed in over- 
coming the friftion /, the velocity in a fecond v, the 
diameter of the pipe J, and its length /; we may make 

-J- v' + 2 c —T v. for it is obvious, that the fri'c- 

in two miles being 8 inches, we have ^/ (8 x 29.13) = 
15.26 for the mean proportional; -i-rths of which is 13.9 
agreeing nearly with Mr. Watt's obfervation. ProfeiTor Ro 
bifon has deduced from Buat's elaborate theorems 12.568 
inches for the velocity, which is confiderably lefs accurate 
r ■ " ..._.. 


and its velocity is obferved to be about 55 inches in a fecond. 
Our rule gives 58, which is perhaps as near as the degree 
of accuracy of the data will allow. 

On the whole, we have ample reafon to be fatisfied with 
the unexpefted coincidence of fo fimple a theorem with ob- 
■ fervation ; and in order to find the velocity of a river from /- 
its fall, or the fall from its velocity, we have only to recol- 
left that the velocity in inches per fecond is | ^ths of a mean 
proportional between the hydraulic mean depth and the fall 
in two Englifli miles in inches. This is, however, only true 
of a ftraight river flowing through an equable channel. 
For the dope of the banks of a river or canal, Mr. Eytel 

wein recommends, that the breadth at the bottom fhould be juftly obferved. 
yds of the depth, and at the furface Vds ; the banks will 

tion muft be direftly as the length of the pipe ; and fince 
the preffure is proportional to the area of the feftion, and 
the furface producing the friftion to its circumference or 
diameter, the relative magnitude of the friftion muft alfo be 
inverfely as the diameter, or nearly fo, as Du Buat has 

then be in general capable of retaining their form. The 
area of fuch a feftion, is twice the fquare of the depth, and 
the hydraulic mean depth f ds of the aftual depth. 

M. Du Buat's Rule. — In our article River, we have 
given the theorem of M. Du Buat for calculating the motion 
of water in a river or other regular channel, or through 
pipes. It has been obferved by the late Dr. Robifon, 
that the comparifoii of the chevalier Du Buat's calculations 
with his experiments is very fatisfaAory ; that it exhibits a 

We fhall then find, that a muft be .ooooooi (413 + ~y 
c muft be .0000001 

'•0563 \^ 
dd I)' 

(.=85 f '-^ + 

\dd+ 1136 "^ ^d V'""^ ' d 

Hence it is not difficult to calculate the velocity for any 

given pipe, open canal or river, with any given column 
beautiful fp'ecimen of the means of cxpreffing the general of water : for the height required for producing the velo- 
refult of an extenfive feries of obfervations in an analytical . . ..j 

formula ; and that it does honour to the penetration, Ikill, city, including friaion, is, according to Du Buat, 
and addrefs of M. Du Buat, and of M. De St. Honore, 

who affifted him in the conftruftion of his expreffions. 

Dr. Toung's Rule Dr. Young juftly remarks, in an ex- 
cellent paper in the Philofophical Tranfaftions for 1808, that 
the form of Du Buat's expreffions is not fo convenient for 
praftice as they might have been rendered ; and are liable to 
great objeftions, in particular cafes : for when the pipe is ex- 
tremely narrow, or extremely lon^, they become completely 
erroneous. Dr. Young has, therefore, fubftituted for the 
formulae of M. Du Buat others of a totally different nature ; 
and he profeffes to have followed Du Buat only, in his general 
mode of confidering a part of the prefTure, or of the height 
of a given fall, as employed in overcoming the friftion 
of the pipe, through which the water flows out of it ; a 
principle which, if not of his original invention, was cer- 
tainly firft pubhfhed by him, and reduced into a practicable 
form. We find Mr. Smeaton ufed it in conftrufting his 
MS. tables. By comparing the experiments which -Du 
Buat has coUefted, with fomeof Gerftner's, and fome of his 
own, Dr. Young difcovered a formula, which appears to 
agree fully as well as Du Buat's, with the experiments from 
which his rules were deduced, and at the fame time accords 
better with Gerftner's experiments ; and which formula ex- 
tends to all the extreme cafes writh equal accuracy. It feems 
to reprefent more fimply the aftual operation of the forces 
concerned ; and it is direft in its application to praAice, 
without the neceffity of any fucceffive approximations. 

He began by examining the velocity of the water dif- 
charged through pipes of a given diameter, with different 


or rather, as it appears from almoft all the experiments 

which the doftor compared, 


and the whole height A 

ii, therefore, equal to / + — — -, or h ■ 


and affuming b := 

I -7- d + .ooiy'i 

and alfo 


alTuming f = —5-, we have d' -\- 2ev = it; whence, 

t> := ,/ {bh + <r') — e; which is a general theorem. 

In order to adapt this formula to the cafe of rivers, we 

muft make / (the length) infinite ; by which i becomes — j, 

and 6h =: 

^ — ; 1 being the Jine of the in- 

clination of the water's furface, and </ = 4 times the hy. 
draulic mean depth. The hydraulic mean depth is the area 
of the feftion of the moving water, divided by as much of 
the circumference of that area, as the water touches. And 
^/ {ads + c') 

fince e is here =: 

and in moft 

rivers, v becomes nearly ^ {20000 ds). 

Another ufeful rule by Dr. Young, is to find the fuper- 
ficial velocity of the water in a river by adding to the mean 



velocity of a river its fquare root ; this gives the velocity 
at the furface ; and by fubtrafting the wme fquare root, 
we get the velocity at the bottom. 

N. B. 2.618 — ,/ 2.618 = I, and .382 + ^/ .382*= I ; 
which it may be ufeful to remember, with reference to this 
laft rule. 

Dr. Young made a comparifon of his general theorem, as 
above, with forty experiments extrafted from the collection 
which ferved as a bafis for Du Biiat's calculations ; and he 
found that the mean error of his formula is -j-^th of the whole 
Telocity, and that of his own V^th only. But, omitting the 
four experiments, in which the fuperficial velocity only of a 
river wa^obferved, and in which he calculated the mean velo- 
city by Du Buat's rules, the mean error of the remaining 36 
is but -i^th, according to Dr. Young's mode of calculation, 
and -i^ih according to M. Du Buat's ; fo that, on the whole, 
the accuracy of the two formulae may be conGdered as prc- 
cifely equal with refpecl to tliefe experiments. 

In the fix experiments which Du Buat has wholly rejefted, 
the mean error of his formula is about -^ih, and that of 
Dr. Young's Trth. In fifteen of Gerftner's experiments, 
the mean error of Du Buat's rule is 3d, that of Dr. Young's 
^th ; and in the three experiments which Dr. Young 
made with very fine tubes, the error of his own rules is ,Vth 
of the whole ; while in fuch cafes Du Buat's formulae com- 
pletely fail. 

It would be ufelefs to feek for a much greater degree of 
Mcuracy, udefs it were probable that the errors of the expe- 

riments themfelve* were lefs than thofc of the calculations. 
But if a fuflScient number of extremely accurate and fre- 
quently repeated experiments could be obtained, it would 
be very polTible to adapt Dr. Young's formula ftill more 
correftly to their refults. 

In order to facilitate the computation. Dr. Young made 
tables of the co-efficients a and c for 44 different values of 
a, both in French and Englifh inches, which may be feen 
in the Philofophical TranfaAions for 1808 ; but inllead of 
inferting them, we (hall give a far more extended table, 
which we have carefully deduced from Dr. Young's formula 
and table, and put it in a form more dire6\ly applicable to 

Let J reprefent four times the hydraulic mean depth of 
an open canal. 

Note. — The hydraulic mean depth is the area of the feflion 
through which the water runs, divided by fo much of the 
circumference of that feftion as is touched by the water. 

Note a/fo. — In cafe of clofe pipes running a full bore of 
water, the diameter of the pipe is four times the hydrau- 
lic mean depth. 

s reprefents the fine of the inclination of the water's 
furface ; that is, the height of the head or rife, divided by 
the length or diflance of the flope in which fuch rife takes 

■V, the mean velocity ^^r fecond, in inches. 

The other fymbols ufed in the theorem are fliewn at tlie 
head of the different columns of the Table. 

Dr. Thomas 


Dr. Thomas Young's Theorem, with a new and enlarged Table deduced therefrom, exprefsly for our Work, for 
calculating the Velocity of Water flowing in Rivers, Channels, or Pipes. 

Theorem. The mean Velocity per Second, 

in inches or -u, is = . 


a'- ) a 



c " 




f ' 






a * 



















































1 3 1 600 



















72 . 









1 850000 





1. 701 

























1. 212 























1.418 " 

1. 191 


































2 1 17000 













1. 717 

1. 310 
























1. 711 














- 1 163000 
















1 310000 














































































* 2.337 


























Ufe of the Table.— To render this theorem ufeful to thofe 
who are not familiar with the ufe of algebraic expreflions, 
we (hail give an example of the manner of calculatmg a 
ftream of water, all the operations being performed by com- 
mon arithmetic, with the help of the preceding Table. 

I. If it is a ftream of water running in an uniform chan- 
nel, take a fufBcient number of dimenfions of the tranfverfe 
feaion of the channel, and by the rules of menfuration cal- 
culate the area of its crofs fedion in fquare feet. Calculate 
alfo, how much of the circumference of fuch crofs fedion is 
touched by the water, not including its level top. 

Then divide the area in fquare feet by that portion of the 
circumference in feet, in order to obtain the hydraulic mean 
depth; this muft be multiplied by 12, to reduce it to inches. 
Multiply the quotient by 4, and the refult is d, the number 
which is to be fought in tlie firft column of the preceding 

Table. , , .rue 

If it is a circular pipe of uniform bore, running tull ot 
water, its internal diameter, taken in inches, is already 
equal to four times the hydraulic mean depth, without any 
computation ; and accordmgly the diameter of the pipe in 
inches is to be fought for in column i. 

2. By a fpirit-level or otherwife, afcertain the perpendi- 
cular fall or difference of level, between any two diftant 
points on the furfiace of the water, if it is an open ftream, 
and fi«d the diftance between thefe points of levelling, by 
meafuring upon a parallel to the furface of the ftream. 
Thefe may be taken in any convenient meafures ; but the 
fall and the diftance muft be reduced to the fame meafures : 
then divide the fall by the diftance, and the quotient is /, or 
a decimal number, which is the/n< of the inclination of the 

If it be a clofe pipe, the perpendicular fall muft be the dif- 
ference of level between the furface of the refervoir and the 
place of difcharge ; divide this by the length of the pipe. 

3. Having found d, in column I of the Table, take out 
the number oppofite to it in the fecond column, entitled 

-— (that is, ^/ divided by a), and muhiply this tabular num- 


ber by the decimal number s. 

Note It will fometimes happen that the exaft amount of 

d is not to be found in column i, but it will fall between two 
of the numbers therein ; then take out the leaft of thofe num- 
bers before d, and find how much is to be added thereto, by 
the following rule : Take the difference of the two numbers 
in col. I. between which t/ falls ; alfo the difference of the 
numbers oppofite to them in col. 2.; alfo take tlie difference 
between the number d, and the leaft of the two numbers be- 
tween which it falls. Now, by the Rule of Three, fay, as 
the whole difference of the two numbers in col. i. is to 
the fame in col. 2., fo is the difference between d and the 
number above it in col. i. to a fourth number, which is 
the proportional part to be added to the number of col. 2. 
before d. 

4. Take out the tabular number from col. 3. which is 

entitled ~ ; (that is, the fquare of c divided by the fquare 

of a). 

But here note, in cafe of calculating a proportional part, 
(as direfted in the laft rule,) it is not always to be added (as 
in col. 2.) ; but fometimes, on the contrary, it is to be fub- 
trafted, accordingly as the numbers in that part of col. 3. 
arc increafing or decrcafing ; and for greater eafe of difco- 
vcring this, a* is placed oppofite 14, and between 200 and 
300 of col. 1., to (hew the places where thefe changes take 
place, from decreafc to increafe, and the contrary. 

c. Multiply /, the refult of the fecond operation, and -» 

the refult of the third operation, together, and to the pro- 

duft add —7, as found by the fourth operation : then «xtraft 

the fquare root of this fum. 

6. Take out — from col. 4., and apply the proportional 

part as before, if neceffary ; dedu£l this number — from 

the fquare root laft found, and the remainder or refult is the 
mean velocity of the ftream in inchet per fecond, which waa re- 

Should this refult be afterwards wanted m feet perminute, 
the numbers laft obtained muft be multiphed by 60, and di- 
vided by 12 ; or rather, multiplied at once by 5, which is 
the fame thing. 

To obtain the quantity of water difcharged in a" minute, 
multiply the area of the fedion of the ftream by the velo- 
city now found ; taking care, if the area is in fquare feet, 
toexprefs the velocity of the water in feet ; or if the area is 
in fquare inches, the velocity muft be expreffed in inchef, 
and the produA or refult will be in cubic feet or cubic 
inches, accordingly. 

Example 1 . — The Academy of Sciences at Paris were oc- 
cupied, during feveral months, with an examination of a 
plan propofed by M. Parcieux, for bringing the water of 
Yevette into Paris ; and, after the moft mature confideration, 
gave in a report of the quantity of water which M. De Par- 
cieux's aqueduft would yield. Their report was afterwards 
found erroneous in the proportion of at leaft 2 to 5 ; for 
when the waters were brought in, they exceed the report in 
this proportion. Indeed, long after the giving in the re- 
port, M. Perronet, the moft celebrated engineer in France, 
affirmed, that the dimenfions propofed were much greater 
than were neceffary ; and faid that an aqueduft of 5^ feet 
wide, and 35 deep, with a llope of 15 inches in a thoufand 
fathoms, would have a velocity of 12 or 13 inches per 
fecond, and would bring all the water furnifhed by the 
propofed fources. The great diminution of expence oeca- 
iioned by the alteration, encouraged the community to under- 
take the work. It was accordingly began, and partly exe- 
cuted. The water was found to run with a velocity of near 
19 inches, when it was 3^ feet deep. 

M. Perronet founded his computation on his own expe- 
rience alone, acknowledging that he had no theory to in- 
ftruA him. 

Let us examine this cafe by our theorem. 

Firft, The area of the feftion is 3.5 feet deep x by 5.C 
feet wide = 19.25 fquare feet. — Tlie circumference which 
the water touches, confifts of the two fides of 3.5 feet each, 
added to 5.5 feet, the bottom = 12.5 feet. The area 19.25 
fquare feet divided by 12.5 feet gives 1.54 feet, for the hy- 
draulic mean depth x 12 = 18.48 inches ; four times this 
ii d =: 73-92, which we are to fcek in the firft column of 
the table ; and may take 74. 

Secondly, To find /, take the fall 15 inches, or 1.33 feet, 
and divide it by the diftance, 1000 fathoms, or 6000 feet ; 
the refult is .00022, for /, or the fine of the inclination. 

Take out from the table 
the numbers correfpond- 
ing to 74. 



a ' 








We now have all the neceflary quantities for making the 

ealculation thus : multiply — = 1875000 by j = .00022, 

and we have 416.25. To this add — = 4.872, and it makes 

421.122, of which extraft the fquare root, and it is 20.52 ; 

deduft — = 2.207 from this, and it leaves 18.313 inches 

per fecond for the mean velocity of the water. 

This agrees pretty well with the obfervation of 19 inches, 
and Dr. Robifon made very nearly the fame refult by a diffe- 
rent mode of calculation. 

The velocity of 18.313 inches per fecond X 5 gives 
91.56 feet per minute, and again multiplied by 19.25 fquare 
feet, (the area of the feftion,) gives 176 1.6 cubic feet of 
water which flow through this canal every minute. 

This example is comparatively eafy, becaufe the table 
affords the numbers required ; but in fome cafes the exaft 
numbers cannot be found in the table, we fhall therefore give 
another example. 
• Example 2. — Mr. Watt meafured a canal in the neigh- 
bourhood of Birmingham, which was 1 8 feet wide at the fur- 
face of the water, 7 feet wide at the bottom, and 4 feet deep. 
The water had a declivity of four inches in a mile ; — required 
the velocity with which the water moved, and the quantity 
which the canal afforded. 

To have a complete knowledge of the feftion, find the 
length of each Hoping fide, thus take the projeftion of the 
top width over the bottom width on each fide, that is, half 
the difference between the top and bottom width ( 18 — 7 ) 
— ;- 2 = 5.5 feet : now the fquare of 5.5 is 30.25, and the 
fquare of 4 feet the depth is 16, the fum of the two is 
(30.25 -|- 16 ^ ) 46.25 ; and the fquare root of this is 6.8, 
the length of each Hoping fide. 

Firft, To find the area and the hydraulic mean depth 

The mean between the widths of the top and bottom is 
( 18 -\- 7)-r 2 12.5 X 4 feet deep = 50 fquare feet for the 
area of the feftion. To find the circumference which the 
water touches, add the twofloping fides, each 6.8 feet, to 7 
feet, the vv'idth of the bottom, and it makes 20.6 feet. 

The area, 50 fquare feet, divided by 20.6 feet, gives 2.4272 
feet = 29. 126 inches for the hydraulic mean depth ; 4 times 
this is 116.504, which is d, and muft be found m the firft 
column of the table. The nearcft which can there be found 
is 100 inches. 

Secondly, The fall is 4 inches in the diftance of a mile, 
= 63360 inches, divide 4 by 63360, and it gives .00006313 
for s, the fine of the inclination. 

Thirdly, The value of — , in the iecond column, oppofite 

to 100 in the firft column, is 2501000, to which fomething 
mufl be added for the 16.5 inches. To find this quan- 
tity, take the difference between the adjacent numbers in 
column two, wz. 2501000 and 4950000 = 2449000, and, 
laftly, the difference between 100 and 116.5 = 16.5 ; then 
fay, as 100 is to 2449000, fo is 16.5 to 404085, which num- 
ber is to be added to 2501000, =: 2905085, which is — 


for 1 16.5. 

Fourthly, The value of — , in column third oppofite to 

100, 135.272, to which add .0<i}.3, as found by a rule of 

proportion fimilar to the above, and it gives 5.276) which is 

—r for 116.C. 
a' ■' 

Fifthly, Multiply s = .00006313 by 2905085, and it 
gives 183.395; add —^, or 5.276, as found by the pre- 
ceding operation, and it gives 188.671 ; and the fquare root 
of this number is 13.736. 

Sixthly, The value of — , in column fourth, is 2.296 for 

100, or for 1 16.5 it is 2.297 ; deduft this from 13.736, the 
refult of the laft operation, and we have 1 1.439, which is the 
velocity of the ftream in inches /ifr fecond, and' this x 5 = 
57.195 feet per minute. To find the quantity, multiply 
the velocity, 57.19 feet per minute, by 50 fquare feet the 
area, and we fiiall have 285.97 cubic feet, which quantity 
will flow every minute through this canal. 

The velocity here found is confiderably fmaller than what 
was obferved bv Mr. Watt ; lie found the velocity at the 
furface 17 inches per fecond, and at the bottom 10 inches, 
the mean velocity we have already calculated at 13.32. 

Dr. Robifon, in the Encyclopedia Britannica, gives a 
calculation of this fame cafe by Du Bual's formula, which 
we have given in the article River. He makes the velo- 
city 11.85 f^'-''^ /"■'■ fecond, which differs fo little from our 
computation, that the two theorems may be confidered 
equally accurate ; but both appear, by Mr. Watt's obferva- 
tion, to be rather too fmall in very fmall dechvities of 
rivers and canals. This is not furprifing when we confider, 
that the experiments, which are the foundation of both 
thefe formulae, were made on fmall canals ; but for this 
reafon, we may expeft they will be more accurate when 
apphed to fmaller channels, fuch as mill-courfes, aque- 
dufts, &c. 

In taking obfervations to apply this method of calculation 
to praftice, it muft be recollected that it always proceeds on 
the fuppofition, that the canal is of a, regular width and 
depth, and of an uniform Hope throughout. If this is not 
the cafe, the canal muft be confidered in different portions, 
and each calculated feparately. We think greater accuracy 
will be attained by meafuring Jind carefully levelling 100 
yards in which the width and depth are quite regular, than 
by taking a mile in length, if there are any irregularities 
in the dimenfions, or in the dope in that diftance. 

On the other hand, the theorem cannot apply at all, unlefs 
the length of the channel is fuch, that the water in it will 
arrive at an uniform motion without any acceleration of the 
motion, as it proceeds down. In fhort and rapidly inclined 
channels, the water accelerates in confequence of defcending 
further down the fall ; but when the canal is long, the ve- 
locity arrives at a certain point, and then the friftion pre- 
vents any farther acceleration ; in this cafe, the theorem ap- 
plies. We fhall not err fenfibly in ufing this theorem for 
canals of 30 yards in length, or lefs, if the fall is fmall. 

Method of gauging the Water running through clofe Pipes. — 
Dr. Young's theorem and our table, apply with equal, per- 
haps greater accuracy, to the cafe of clofe pipes than to open 

All that is neceffary is, to meafure the internal diameter 
of the pipe in inches, the length of the pipe, and the diffe- 
rence of the level between the water in the refervoir and the 
place at which the water is difcharged, and proceed as in 
the former inftance ; but to render it more clear we fhall 
give two examples. 

Example i The city of Edinburgh is fupplied with 

P water. 


witer, from fprings at Comifton, which is a confiderable dif- 
tance ; tliis is conveyed by two pipes, the firft of which was 
laid in 1720, under the diredioii of Dcfaguhers. Dr. Ro- 
bifon mentions one of them, which is 5 inches diameter, 
14,637 feet in length; tlie rcfervoir at Comillon is forty- 
four feet higher than the refcrvoir on the CalUe-Hill, in the 
town of Edinburgh. 

Firft, to find the fine of the inclination, or s, divide the 
fall 44 feet by 14,637, and it gives .00301, which is s. 

Now take five inches, the diameter of the pipe in col. I., 

and oppofite to it in col. 2. find — = 1597CO, which mul- 
tiply by .00301, gives 479.1 ; to this add— = 2.624tak.en 

from the third column, and the fum is 481.724. 

Extraft the fquare root of this, and it is 21.948, from 

which dedua — , or 1.620, taken from col. 4., and the re- 

fult is 20.328, which is the velocity in inches per fecond, 
and this x by 5 = 101.64 feet /)fr minute. 

To find the quantity, find the area of the feftion of the 
pipe in fquare feet, by dividing the fquare of the diameter 
25 by 183.3, ^"'^ '*■ g'^*^* .1364 fquare feet, and this x by 
101.64 feet velocity, gives 13.86 cubic feet per minute for 
the difcharge from the pipe. 

Dr. Robifon's calculation of this fame cafe by Du Buat's 
formula, gives a velocity of 20. oS inches />fr fecond. 

In Mr. Smeaton's Reports, we find the other pipe ftated at 
four and a half inches bore, and that it yielded 160 Scots 
pints ^fr minute, each 103.4 cubic inches = 9.58 cubic feet. 
Mr. Smeaton's own calculation was 159 pints. 

Example 2 Mr. Smeaton ftates, that this pipe was im- 
proved by obtaining an increafe of fall, making it 51 
feet, and that it then yielded 200 Scots pints = 11.98 
cubic feet per minute, the bore being 4^ inches, and the 
length 14,637 feet as before. Mr. Smeaton's calculation 
was 173 pints = 10.36 cubic feet per minute. What 
would it be by Dr. Young's theorem ? wis. velocity = 

\/(t^^ + 7')-T 

The fquare root of that number is 22.609, from which 
deduft — ,= 1.854, and it leaves 2C.755, which is the velo- 
city per fecond in inches. 

[Note. ■ — is found by fubtrafting half the difference be- 
tween the numbers for 4 and 5 in tlie fourth column, from 
the number anfwering to 4.) 

20.755 incl'cs per fecond x 5 = ic3.775 feet per mi- 
nute, tor the velocity. The area of the pipe is 4.5 x 
4.5 = 20.25 circular inches, which -j- by 183.3, the circular 
inches in a iquare foot, is ^ .1 104 fquare feet for the area 
of the pipe. Multiply this by 103.775 feet per minute, and 
we get 1 1,46 cubic feet per minute for the difcharge, which 
agrees very nearly with the experiment. 

Dr. Brewfter, in his Encyclopsedia, has calculated this 
fame pipe, except that he ftates it 300 feet longer ; he 
makes the velocity by Du Buat's theorem 20.385 inches /i^r 
fecond, and fays that on an average of five years, from 1738 
to 1742, its maximum difcharge was 11.3 cubic feet per 
minute ; he has alfo calculated the fame cafe by five different 
formulse ; thus, 

To find s, divide the fall 51 feet by the length 14,637 
feet ; it gives .003484. 

To find — , anfwering to 4.5 inches in col. i., take half 
the difference between the numbers in the fecond col. op- 
pofite to 4 and 5, and add it to the number anfwering to 

4; thus, — for 4 is 13 1560, and — for 5 is 159700, 

difference 28200, which -=- 2 = 141 00, and this x 131500 

= 145600, which is — for 4.5. Multiply this 145600 

by /, or .003484, and it is = 507.67 : to this add -^. 

To find — for 4.5, take half the difference between the 

numbers in the third column for 4 and 5, which is .869, 
and fubtraift it from 4.363, the number anfwering to 4; 

the refult is 3-494, which is -- for 4.5 ; this added to 

507.67 is 511.164. 

The quantity of water aftually 
difcharged . . . 

Calculated by Eytelwein's for- 
mula . . . . 
Calculated by Girard's formula 
Calculated by Du Buat's formula 
Calculated by M. Prony's fimple 
formula . . - . 
Calculated by M. Prony's table - 
To which we may add Mr. Smea- 
ton's calculation - - - 
And by Dr. Young's theorem - 

Scot's Pini 
per Minuii 

1 200 

3 '89-4 
J 189.77 


j 19232 

} 173- 

Cubic Feet 
per Miuiue. 


1 1.265 

1 1.502 

It is fatisfaftory to find the rcfults of fo many different 
proceffes agree fo nearly, and gives us great confidence 
in the truth of the principles. There is in this cafe fo little 
difference amongft theorems that any one may be taken ; 
but we think it needlefs to enter into farther particulars, as 
the one which we have given effcfls all that can be defired, 
and by the help of the table, is the moft ready in the appli- 

We ffiall only add Mr. Smeaton's table on the friAion of 
water running through pipes, which we find 1 his manu- 
fcript papers, and which he computed from his own 
obfervations alone, without knowing the experiments on 
which the other theorems are founded. They will give ra- 
ther lefs than the theorems, and perhaps may approach more 
nearly to aftual praflice, in which pipes arc not laid with the 
fame care, to avoid roughncfs withinfide and fudden bends, as 
when prepared purpofely for experiments ; we may confider 
the theorems as the maximum difcharge, and Mr. Smeaton's 
table as the fair average of practice. 

Ufe of the Table. — Find the velocity of the water *cr 
minute in feet and decimals in the firft column, or in feet 
per fecond in the next column, and on the fame line under- 
neath the diameter of the bore in inches, you will "find the 
perpendicular height of a column of water in inches and loths, 
neceffary to overcome the friftion of that pipe for 100 feet 
in length, and obtain the giren velocity. 

9 Mr. 


Mr. Smeaton's Tadll lor lliewing the Fridlion of Water in Pipes ; the Bore of the Pipe being given, and the Velocity 
of the Water therein ; the Column or Height of Head neceffary to overcome the Friftion, and produce that Velocity 
is (hewn by this Table for loo Feet in Length. 

Bore of the Pipes in Inches. 














In Feet 


In Feet 


Depths of Water neceffary to 

overcome the Friftion of the Water in a 

Pipe IOC 


long, and produce the Velocities marked in th 

e two firft Columns. 
























































































































































































II. I 



























1 1.4 



























II. 7 
































































































II. I 




















































































































































61. 1 






















































112. 1 



















ore of tl 

le Pipes 

n Inche 



Mr. Smeaton's Table for the Fridion in Water in Pipes — CmtinutJ. 


Bore of tl 

10 Pipes in Inches. 












In Feet 

In Feet 


of Water neceffary to overcome the Fri£tion 

of the Water in 

a Pipe 100 feet | 




and prod 

uce the Velocities marked in 

the Two 

























































0.1 I 

















































































































1. 166 




































1. 416 



























































1 10 










































































12. 1 













12. 1 













12. 1 



















































II. 2 

1 0.0 



















2 3-8 

21.4 , 




1 1.9 















10. 1 

















































of the Pipes in Inc 




We have fearched in Mr. Smeaton's papers for the experi- 
ments by which this table was made, and we find an invefti- 
gation, from the experiments of M. Couplet, as recorded by 
Belidor, on the floxv of ' ,'aier through a large pipe at Ver- 
failles. From thefe he deduced the following rule, to find 
the height of column in inches, correfponding with the ve- 
locities in inches per fecond, through a pipe of any diameter 
given in inches, and loo feet long. 

48 X (velocity) 4- velocity'' j ^, r 1 

~ — — ^—— i^p — '— =; depth ot column ; 

52.60 X (diameter) 

or, ftill more nearly, taking 47.873 for the conftant number 
inftead of 48. 

It appears that he found this rule did not agree vrith his 
own obiervations ; and, in confequence, he made the follow- 
in<j- experiments himfelf with a pipe of 1:5 inch bore and 100 
feet in length ; and we believe he arranged them into the 
table, by projefting and drawing a curve, at leaft we find 
that was his ufual method in like cafes. 



Depth of the Column. | 

By tlie Table. 

By Experiment. 

luches , 





























18. 1 






















This is ufeful information, becaufe it fhews what part of 
the table may be depended upon. He aflumed, that t+ie 
depth of the column in pipes of other dimenfions, was as the 
length of the pipe direftly, and as the diameters inverfely. 

The form of this table renders it immediately apphcable 
to a great variety of purpofes ; for inftance, an engine is re- 
quired to pump water to a height of 60 feet ; but the water 
mud pafs through 1800 feet of horizontal pipe of 5 inches 
bore, and %vith a velocity of 140 feet per minute. The table 
(hews, that for every 100 feet of this pipe the friftion will be 
equal to a column of 7.6 inches ; multiply this by 18.6, and 
we find the whole friftion will be 141.36 inches, this added 
to 60 feet makes 71.78 feet for the real column which the 
pump muft overcome. 

Rules for meafitr'mg the Quantify of Water Jtowlng through 
Sluices or apertures. — In this, like the former inftances, we 
muft multiply the area of the aperture by the velocity with 
which the water rufhes through it. 

Sir Ifaac Newton, in his Principia, book ii. theo. 8. 
prob. 36. has demonftrated, that the velocity of water, 
flowing throi'gh holes in the bottom or fide of a vefTel, 
ought to be equal to the velocity which a heavy body would 
acquire, in falling through a fpace equal to the di!':ance be- 
tween the furface of the water and the place where it is 

Hence, at the depth of i6tV feet, a ftream of 32^ feet 
in length, ought to flow out in a fecond of time. And from 
the laws of falling bodies, it follows, that as the fquare 
root of i6tJ3- is to the velocity of the ftream flowing out at 
that depth, fo is the fquare root of any other depth to the 
velocity of that depth. 

Hence, the velocity of water flowing out of a horizontal 
aperture, in the bottom of a ciftem or refervoir, is as the 
fquare root of the height, or the depth of water above 
the aperture. 

That is, the prefi"ure, and confequently the depth, is as 
the fquare of the velocity ; for the quantity flowing out hi 
any given time is as the velocity, and the force required to 
produce a velocity in a certain quantity of matter in a given 
time, is alfo as that velocity ; therefore, the force muft be 
as the fquare of the velocity. 

The propofition is fuUy confirmed by BofTut's and Mi- 
chelotti's experiment ; the proportional velocities, with a 
preflure of i, 4, and 9 feet, being 2722, 5436, and 8135, 
inftead of 2722, 5444, and 8166; very inconfiderable dif- 

There is another mode of confidering this propofition, 
which is a very good approximation. Suppofe a very thin 
cylindrical plate of water, like a wafer, Ctuated in the ori- 
fice ; and fuppofe a conftant fucceflion of fuch plates to be 
put in motion, one at every inftant, by means of the pref- 
fure of the whole cylinder ftanding upon it ; let all the 
gravitating force of the column be employed in generating 
the velocity of each fmall cylindrical plate, (negleiting the 
motion of the cylinder itfelf,) this plate would be urged by 
a force as much greater than its own weight, as the column 
is higher than itfelf, and this through a fpace fliorter in the 
fame proportion than the height of the column. But where 
the forces are inverfely as the fpaces defcribed, the final 
velocities are equal : therefore, the velocity of the water 
flowing out muft be equal to that of a heavy body falling 
from the height of the head of water. 

This velocity may be found very nearly by the rule 
which we have before given in underftiot water-wheels, or 
by extrafting the fquare root of the depth in feet, and mul- 
tiplying it by 481.2 : the produft is the velocity ^?r minute 
in feet. 

In praftice it is more convenient to take the depth in 
inches, inftead of feet ; then to obtain the velocity in feet 
per minute. 

Extract the fquare root of the depth in inches, and mul- 
tiply it by 138.88 : the produft is the velocity in feet 
per minute. 

As this rule is the foundation of all calculations for 
velocities, when friftion is not confidered, it is conftantly 
wanted : we fhall, therefore, give a table, calculated by 
Mr. Smeaton from the above rule, fhewing the theoretic 
velocities correfponding with different depths. 

A Table 


A Table /hewing the Velocity in Feet per Minute, or per Second, with which Water llioiild idue fiuni an Aperture at 
any given Depth beneath the Surface, from \ Inch to 20 Feet, calculated according to the Theory of falling Bodies. 

■^ Mimiic. 






































VeU>ciiv /)fi 

1. 16 

















Velocity ^yr niff ^flocity per 
Minute. Second. 





62 1. 1 

694 2 








101 1.6 

































Velocity ^ 



































































If we were to calculate the expeiice or difcharge for 
any orifice by this table, we (hould in every inftance find 
it much greater than nature really gives us. 

It mult be recolledled, that this table is not calculated 
from experiment, but from the theory of falling bodies, 
which makes no allowance for the lofs of velocity, which 
arifes from the friftion of the particles of water againft 
the edges of the aperture, and againft the neighbouring 
particles of water which are not put in motion. 

Sir Ifaac Newton, in making experiments, found the 
velocity thus determined to be too great, which in one cafe 
hecorrefled. The friftion againft the fides of tlie aperture, 
and the oblique dire&ion of the particles of water before 
they reach the aperture, both tend to diminifli the velocity of 
the ftream ; and if thefe caufes could be removed, cfpecially 
the .alter, the Newtonian theory would be confirmed by 
experiment, or rather experiment would exaftly agree with 

For, if we fuppofe water running into the top of a cy- 
lindrical tube, and that there is no attraftion or friftion 
between the particles of water and the interior of the tube, 
the velocity of the water, or of each of the particles at the 
bottom, would be the fame, or equal to that which they 
would have acquired in falling through the fame fpace with- 
out the tube, towards the earth. 

Hence, to obtain the true velocity, under different cir- 
eumilances, we muft correft the computed velocity by 

It is ftated in feme elementary works on hydroftatics, 
that the velocity of the water at the orifice is only equal to 
that which a heavy body would acquire by falling through 
half the height of the fluid above the orifice. This was firft 
maintained by fir Ifaac Newton, who found that the dia- 
meter of the ftream is contrafted, after it has quitted the 
orifice ; and at the fmalleft part, the diameter was to that 
of the orifice as 2 1 to 25. The area, therefore, of the one 
was to the area of the other as 21' to 25', which is nearly 
the ratio of i to the fquare root of 2. By meafuring 
the quantity of water difcharged in a given time, and alfo 
the area of the vena contrafta, fir Ifaac found, that the velo- 
city at the vena contrafta was that which was due to the 
whole altitude of the fluid above the orifice. He, there- 
fore, concluded, that fince the velocity of the orifice was to 
that at the vena contrafta as i to the fquare root of 2, the 
velocity in the vena contrafta was that which was due to the 
whole altitude of the fluid ; and that the velocity at the 
orifice muft be that which is due to one half that altitude, 
becaufe the velocities are as the fquare roots of the heights. 
From this, fir Ifaac ftated the aftual velocity of flowing 
water to be -tttVs! ot .707 of the theoretic velocities. 

But the real quantity of the reduftion varies in different 
cafes, according to the nature of the aperture : hence, it is 
necelfary to confider all different forms of apertures, and 
make a different allowance for each cafe. To do this, the 
circumftances of the aperture muft be carefully examined. 

A, Jig. 8. Plate II. Water-works, explains the manner 
in which the filaments of water may be fuppofed to move, 
when a ftream flows through an aperture in a thin plate. 

B ftiews the motion, when a tube of about two diameters 
in length is added to the orifice, and when the water flows 
through the tube with a full ftream. This does not always 
happen in fo fliort a pipe, and never in one that is fliorter ; 
but the water will frequently detach itfelf from the fides of 
the pipe, and flow through it with a contrafted jet. 

C fhcws the motion, when the pipe projefts into the in- 
fide of the veffel. In this cafe, it is difBcult to make the 
tube flow full. 

D reprefents a mouth-piece fitted to the hole, and formed 
agreeably to that ftiape which a jet would affume of itfelf. 
In this cafe all contraftion is avoided, becaufe the mouth 
of this pipe may be confidered as the real orifice ; and no- 
thing now diminifhes the difcharge but a trifling friftion of 
the fides. 

When water iffues through a hole in a thin plate, the 
lateral columns, preffmg into the hole from all fides, caufe 
the iffuing filaments to converge to the axis of the jet, and 
contraft its dimenfions after it has quitted the hole, and at 
a little diftaiice from the hole ; and it is iu this place of 
greateft contraftion that the water acquires that velocity 
which we affume as equal to that acquired by falling from 
the furface : therefore, that our computed difcharge may 
beft agree with obfervation, it muft be calculated on the 
fuppofition that the orifice is diminiftied to the fize of 
this fmalleft feftion. But the contraftion is fubjeft to 
variations, of which the reafons are not .ipparent. 

The following are the meafures of the contrafted vein, as 
afcertained by different authors ; the area of the aperture 
being 1000, the area of the contrafted vein at the fmalleft 
will be as follows : 

Sir Ifaac Newton 

Poleni - . . . . 

Greateft found by Boffut 

Mean of fix experiments by Boffut 

Loweft found by Boffut 


Michelotti . . . . 

Du Buat 

Venturi . . . . . 
Eytelwein . . . . . 



The meafures giTen by Boffut were taken by a pair of 
fpherical compaffes, with which he meafured direftly the 
diameter of the contrafted vein, which he found to preferve 
the fame diameter for fome lines. The altitude of the water 
in the refervoir which Boffut ufed was 12 feet 6 inches. 
He meafured the vena contrafta alfo, when the water iffued 
by vertical orifices placed 4 feet 3 inches below the furface 
of the fluid, and he obtained the very fame refults. The 
ratio between the area of the orifice and the area of the vena 
contrafta appears from the above, to be by no means con- 
ftant. It undergoes perceptible variations, by varying the 
form and pofition of the orifice, the thicknefs of the plate 
in which the orifice is made, the form of the veffel, and the 
velocity of the iffuing fluid. 

The dimenfions of the fmalleft feftion of the contrafted 
vein are at all times difficult to be afcertained with precifion. 
It is, therefore, much more convenient to compute from the 
real dimenfions of the orifice, and to correft this computed 
difcharge by means of an aftual comparifon of the computed 
and effeftive difcharges, in a feries of experiments made in 
fituations refembling thofe cafes which moft frequently 
occur in praftice. 

We have made a colleftion of experiments by various 
authors, and from them we have deduced the following rule 
for the real velocity with which water iffues from an aper- 
ture in a thin plate. 

Rule. — Meafure the depth of the centre of the orifice be- 
neath the furface of the water in the refervoir in inches, 
extraft its fquare root, and multiply it by the conftant number 
85.87 : the produft is the velocity in feet per minute. 

If the velocity, as marked in the preceding table, is mul- 
tiphed by .618, the fame refult will be obtained. For the 
contraftion of the ftream or vein of water, running out of a 
fimple orifice in a thin plate, reduces the area of its feftion, 



at the diftance of about half its diameter from the orifice, 
from I to .665, according to the mean different llatements 
above quoted : hence the diameter is reduced to .815. 

The quantity of water difcharged is very nearly, but not 
quite, fufficient to fill this feftion with the velocity due, or 
correfponding to the height. For finding accur.^tely the 
quantity difcharged, the area of the orifice muil be fupporcd 
to be further diminilhed to .619 on account of fridion. 

In regard to the accuracy of this rule, we mud refer to 
the following table, which contains the refults of 35 expen- 

ments, and alfo the calculation for each. We have been 
obliged to rejeft about 1 2 other experiments, becaufe they 
would not accord with the theorem ; but in nearly all of 
them, the velocity was greater than the rule, and thofe 
which are lefs we have preferved. This was done, becaufe 
we fufpeA that many of the cafes were not apertures in thin 
plates ; but in wood planks of confiderable thickncfs, fuch 
as fluices, the difcharge would then be greater than our 
rule fuppofes, and fuch cafes (hould be clalfcd with another 
defcription of aperture. 

Table of Experiments on the EfBux of Water from Apertures on thin Plates. 

Depdi in Inghes 

of the Cenire cif 

he Orifice beneatli 

the Surface. 

Smeaton and Brindley 


Poleni . . - 

Smeaton - - - 



Venturi . . - 


Venturi - - - 

Smeaton - - - 


Smeaton • - - 

Boffut - 

Boffut - 



Boffut - 






























Velocity of ihe 

effluent Water 

per Minute 

in Feet. 


307 + 

307 = 

381 - 

432 + 

432 + 

434 = 

460 — 

5^5 + 

508 + 

531 = 

553 - 

608 + 

6.3 = 

751 = 

790 = 

807 + 

805 = 

803 = 

810 = 

866 = 

918 = 

967 = 

1014 = 

1 03 1 = 

1035 - 

fi047 - 

1 1050 =. 

1055 = 

1438 + 

1414 - 

1416 — 

1417 - 
1404 - 
1446 + 

Velocity caicu- 
latfd, by inuUi- 
plyinc; the Square 1 
Root of llu' Depth 

bv 85. S7. 

Defcription of ihc 



















869 I 
920 I 

971 1 

105 1 


'43 « J 



I inch fquarc. 

2^ circular 
I inch fquare. 
I inch fquare. 

iv'a inch fquare. 
tV inch circular. 
i\ inch circular. 

I iV circular. 
1 inch fquare. 
\ an inch circular. 

I inch fquare. 

3 inches fquare. 
1 inch fquare. 
3 inches fquare. 

I inch circular. 

3 inches circular 
3 inches fquare. 

I inch circular. 

1 inch fquare. 

3 inches circular. 

3 inches fquare. 

2 inches circular. 
I inch circular. 

Thefe are the refults of the difcharge through orifices in 
a thin plate. If we apply to the orifice tlie Ihortell cylin- 
drical pipe, that will caufe the ftrcam to adhere every where 
to its fides, we (hall find that its length muft be twice its dia- 
meter. The difcharge through fuch a tube will be about 
Vths of the full quantity, and the velocity may be found 
by multiplying the full velocities marked in our firft Table 

by .8125. . , , . . , J u • 

The greateft diminution of velocity is produced by m- 

ferting the pipe fo as to projeft witliin the infide of the re- 
fervoir ; probably becaufe ot the greater interfcroircc of the 
motions of llie particles approaching its orifice in ;ill direc- 
tions : in this cafe, the velocity is reduced nearly to half of 
tiie full velocity. 

It was one great aim of the experiments of Michelotti 
and Boffut to determine the effefts of contraftion in different 
cafes. Michelotti, after carefully obferving the form and 
dimenfions of the natural jet, made various mouth-pieces re- 



fembling it, till he obtained one which produced the fmalleft 
diminution of the computed difcharge, or till the difcharge 
computed for the area of its fmaller end approached the 
neareft to the eFeftive difcharge. And he at lall obtained 
one, which gave a difcharge of 983, when the natural dif- 
charge would have been 1000. This piece was formed by the 
revolution of a trochoid round the axis of the jet, and the 
dimenfions were as follow : 

Diameter of the outer orifice = 36 

inner orifice = 46 

Length of the axis := 96 

Eytelwein dates that a conical tube, approaching to the 
figure of the contraftion of the ftream, procured a difcharge 
equal to .92 of the full velocity ; and when its edges were 
rounded off, of .98, calculating on its leaft feftion. 

Venturi has aflerted, that the difcharge of a cylindrical 
pipe may be increafed by the addition of a conical tube at 
the end of it nearly in the ratio of 5 to 2. (See his experi- 
ments in our article Discharge.) Bi:t Mr. Eytelwein 
finds this afiertion fomewhat too ftrong, and obfcrves, that 

when the pipe is already very long, fcarcely any effeft is pro- 
duced by the addition of fuch a tube. He made a number of 
experiments witli different pipes, where the flandard of com- 
parifon was the time of filhng a given vefTel out of a large re- 
fervoir, which was not alwayskeptfull,becaufeitwas difficult 
to avoid agitation in replenifliing it ; but this circumftance 
was rendered indifferent to the refults of the experiments by 
the application of an ingenious theorem. They prove that 
a compound conical pipe may increafe the difcharge to twice 
and a half as much as through a fimple orifice, or to more 
than half as much more as would fill the whole feftion with 
the velocity due to the height ; but where a confiderable 
length of pipe intervenes, the additional orifice appears to 
have little or no effeft. 

The refults of the invefligations of BofTut, Michelotti, 
and Eytelwein, agree in a very fatisfaftory manner refpeft- 
ing the diminution of the difcharge in different cafes ; and 
we have arranged them in the following Table, which we 
recommend to engineers, as affording all the neceffary in- 
formatior; to calculate the difcharge from fluices and 



Dafcription of the Aperture through which 
the Water flows. 


To find the Velocity of the iffuing Water. 
Rule. — Extra<a the Square Root of the Depth, (meafurcd from 

To find the Number of 
Cubic Feet of Water 

between the 

the Centre of the (Jrifice to the Surface of the Water,) and 

which flow 

per Minute 1 

Note.— In taking the meafure for the depth 

real velocity 

multiply b) fome One of the following Nuiobera, according 

tlirou^h each Square | 

of the coiumn which produces tlie velocity, 

and the 

to the Circumftaiices of the Cafe. 

Inch of 

he Area. 

we may in general take it from the furface 
of ttie water to tlie centre of the aperture ; 


velocity, or 



When it Is required to know 
the Velocity in Feet per Minute 

but if the aperture U in a perpendicular 
plane, and of a height creater than one- 
fourth of the whole depth, then the velo- 
city muft be found for the top of the aper- 
ture and alfo for the bottom of the aperture, 

that which is 
due to the 

as iheivn by 

When it is required to know 
the Velocity in Feet/jer Second. 

If the 
Depth is 
in Feet 

exlrafl the 

If the 

Depth is 

in Inches 

fxtraa the 

our firft 

If the Deptli 

If the Depth 

If the Depth 

If the Depth 



and the mean of both taken for the mean 


is in Feet 

is in Inches 

is in Feet 

is in Inchrs 

Root and 

Rout and 

velociiy of the water. 

multiply by 

multiply by 

multiply by 

niuliipl) by 

mullip y by 

[nultiply by 

For orifices in a thin plate 








For the openings of fluices or" 

apertures in the fide or internal 
walls of the refervoir, without 
any fide walls which can ferve 
to condutft the particles of wa- 








ter in a ftream to the aperture , 

■ I. When it projefts" 

withinfide the veffel 

and does not run 

For a fhort 

with a full bore of 
water, but in form 








pipe from 

of acontratftedvein 

within the tube 

two to < 

2. When it projeAs 

four times 
as long as 

withinfide the veflel 
but runs with a full 








the bore, 

bore of water -J 
3. When it does notl 

projeA withinfide > 








of the veffel - J 

For narrow openings, of which the 

bottom is on a level with that of 

the refervoir. Alfo for fmaller 

openings of (luices, when pro- 

vided with fide walls to conduA 

the water to the aperture; alfo } 








for the water-paffage under 

bridges which have fquare piers 

with abrupt projeftions, which 

do not conduft the water regu- 

larly into the paflTage - . 

For wide openings, of which the" 

bottom is on a level with that 

of the refervoir ; alfo for large 
iluices with condufting walls 

in the direAion of the ftream 








and for the water-way beneath 

bridges with pointed piers, 

which conduft the water into 

the paffage 

For a circular orifice or tube formed " 

correfpondent to the contracted 








ftream - - - - . 

For the whole velocity due to the ' 

height according to the theo- 

1. 000 







rems for falling bodies 


To apply tliefe rules for gauging fluiccs, the following which ran through a fiuittle four feet wide, the depth to tli*' 

meafures muft be taken, i. The perpendicular depth of bottom of the aperture was 22 inches, and the ftiuttle was 

the bottom of the aperture beneath the furface of the water, drawn up one inch and one-quarter, fo tliat the depth to the 

2. The perpendicular depth of the top of the aperture, top of the aperture was 20.75 inches ; what is the expen- 

3. The horizontal width of the opening. Then, taking the diture^^r minute ? 
difference between the two firft meafures leaves the height 

The full velocity due to 22 1 z: re 

inches depth is by the table j °^'-° ^"'^'^ {'<■ """"»«• 

of the opening. 

Note. — If the aperture is not in a vertical plane, but in- r):.,„ 
clined, as is frequently the cafe in mill-fluices, then the 
width of the opening muft be meafured on the flope ; but 
the depths mutt always be taken perpendicularly beneath 
the furface of the water. 

To make the calculation, find the mean Telocity of the 
effluent water, by calculating the velocity due to the depth ,. . — — — ^ 

of the top of the aperture, and alfo for the bottom of the Note.-—A% 20.75 's not to be found m tne table, 
aperture, and take a mean of the two. * , *°5 — 628.8, and add to il half the difference between 

//o/f.— When the height of the aperture is lefs than one- ^°5 and 21, viz. 3.9 = 632.7 feet/^r minute velocity for 
fourth of the whole depth, then the velocity due to the depth ^°;2^' *° ^^oj;^' 
of the centre of the aperture will be very near the truth. , ^ he area of the aperture 48 inches, x 1.25 inches = 60 

Having found the mean velocity in feet, multiply it by J^"^?''^ mches, - 144 = .4166 fquare feet. Multiply this 

for 20% 632.7 

Cj^z.i^ mean velocity ^<raiin, 
the table 

by the velocity = 642.15 feet, and it gives 267.5 cubic feet 
per minute difcharged according to theory. 

To reduce this to the praftical difcharge, multiply by 
fome of the numbers in the firft column of the Table oppo- 
fite, according to the nature of the aperture. The fluice was 
in a trough, nearly of its own dimenfions ; fo that the bottom 
and fides nearly correfponded with the aperture ; therefore, 
take .860, and x 267.5 g'^^' ^38 cubic hetper minute. 
It is very convenient to an engineer to be abk to calculate 

jfually marked C and 
Theareaoftheapertureis4feet, which x 7inche5,= 28 -f ^ ! /^ ^""S a line of logarithms, and D a line fimilarly 
I 2 = 2.333 fquare feet, for the area of the aperture ; there- ^"ded on a fcale twice as large. By means of thefe, the 
fore, multiply 940.6 by 2.333, ^nd we have 2194 cubic '1""« root of any number can be extraded and multiplied by 
feet Airr minute, for the quantity difcharged. ^"J number at one operation. To ufe it, find the multi- 

If the depth had been expreffed in inches, it would have Pl'f ^"'?^ '* '° ^^ ^f^*^- "PO" the line D, and fet the 

the number of fquare feet in the area of the aperture, and it 
will give the ijuantity difcharged, in cubic feet. 

Example I. — A fluice, which is four feet wide, is opened 
or drawn feven inches, and the depth of water above the 
centre of the orifice is ten feet. The edges of the fluice 
are cut fliarp, fo that the borders of the orifice arc like a 
thin plate. What is the velocity and difcharge per minute 
in cubic feet ? 

The fquare root of 10 is 3.162, which x 297.45 from the 

table, gives 940.6 feet per minute, for the mean velocity of ^^ difcharge of water by means of the flide-rule. 
the water. '"^ ™^y °° ^Y "T^ans of the two lines ufually marked 

been 120. The fquare root of this is 10.95, and this multiplied 
by 85. 87, gives 940.6 feet ^^r minute for the velocity, as be- 
fore. In like manner, the table gives the proper multipliers 
for finding the velocity in feet per fecond, if it is required. 

If it was only required to obtain the quantity difcharged, 
we may proceed more direftly, thus. The depth is 10 
feet, and the fquare root ia 3.162, x by 2.065, ^^e number 
taken from the laft column but one of the table, and we 
have 6.529 cubic feet, which are difcharged per minute 
from every fquare inch of the aperture. The aperture is 
48 inches, this x 7 = 336 fquare inches, this x 6.529 = 
2194 cubic feet difcharged as before. 

If the depth had been 1 20 inches, then the fquare root of 
that number ^= 10.95, ^"d this x .5963, the number in the 
laft column gives 6.529, as the laft. 

Another method is, to calculate the theoretic difcharge, 
and then make a proper reduftion, by multiplying by the 
decimal number in the firfl column. Thus, by our firft 
table of velocities, 120 inches deep =: 152 1.8 feet per 
minute, this x by 2.333 fquare feet, the area of the aperture 
gives 3550 cubic feet per minute for the theoretic difcharge. 

Aider fo that to upon C will correfpond with it ; then feek 
for the depth upon C, and oppofite to it upon D, the re- 
quired velocity will be found. 

Line on the Aider marked C, depth in inches, 1 o 

Line on the rule marked D, velocity in {eetper minute, 85.8 
And in like manner for any other multipliers : for 
Line on th? Aider marked C, depth in inches 10 

Line on the rule marked D, cubic feet /rcr minute T 

difcharged through a > .596 
fquare inch, J 

Mr. Eytelwein obferves, from Du Buat, that the difcharge 
through an orjfice communicating between two refervoirs, 
and fituated beneath the furface of the water in the lower 
refervoir, is the fame as if the water run into the open air, 
taking the difference of level between the two furfaces, for 
the depth of the column ; he calculates the difcharge when 

jjj - - - - ^^ the water has to pafs through feveral orifices in the fides of 

The firft column of the prefent table fhews that the real as many refervoirs open above. In fuch cafes, where the 
difcharge is only .618 of the theoretic difcharge ; therefore, orifices are fmall, the velocity in each may be confidered 
multiply 3550 cubic feet by .618 = 2194 cubic feet for as generated by the difference of the heights in the two 
the real difcharge, as in all the former cafes. contiguous refervoirs ; and the fquare root of the difference 

This latter method is very convenient, becaufe we can will therefore reprefent the velocity which muft be generated 
apply a different correftion in different cafes, according to in the feveral orifices,inverfely as their refpeftive areas, fo that 
difcretion, and the table of velocities facilitates the calcula- we may calculate from hence the heights of the different 
lion very much. refervoirs when the orifices are given. Mr. Eytelwein alfo 

Example 2. — A flour-mill was worked by the water confiders the cafe of a lock, which ie filled from a canal of 

O 2 «n 


an invariable height, and determines the time required, by tur- beneath the levd furface of ilie water in tlie refervoif 
compiring it with that of a velTel emptying itfelf by the to be 4 inches. The cube of this is 64, the fquare root of 
preffure of the water that it contains, obferving, that the which is 8 ; therefore, at that depth each inch in width will 
motion is retarded in both cafes in a fimilar manner, and difcharge 8 x 11.5 = 92 cubic inches ^^r fccond ; if the 
lie tinds the calculation agree fufficienlly well with expe- width of the aperture was 3 feet, then 92 x 36 inches 
riments made on a large fcale. = 33'2 cubic inches, or 1.917 cubic feet, which x 60 fc- 

Ruletfor meafuring the Quantity of Water ivhich fows .over conds = 1 1.502 cubic feetiitr minute. 
a If'dr, or through an j^perture in the EJgeqf a Board, the Stream Dr. Robifon gives the following table, which is rather 
being open at Top. — I f we fuppofe water running in a regular greater than from the above theorem, and will be found 
iheet over the edge of a large ciftern or refervoir, or through very exaCl, wlien tlie aperture is made in a plank or 
a r«Aangular aperture made in the perpendicular wall or board half an inch or an inch thick, and fo Ctuated that the 
lide of the ciftern, but open at top, we may take the area fides and bottom of the refervoir do not correfpond with the 
of the aperture, and proceed to find the velocity by calcu- edge of the aperture, to lead the particles of water in a 
latjon. current to the aperture. 

When this fubjeft has been confidered theoretically, 
it has been affumed, that the furface of the water at 
the place where it runs through the aperture, is with- 
out motion, becaufe it Hands at the fame level with the 
ftagnant water in the refervoir, and that the velocity 
of the water at difFerent depths will Iways be as the 
fquare root of the depth ; that is, beginning at nothing at 
the furface, the velocity at different depths will increafe by 
that law. 

We can find the velocity at the bottom of the aperture, or 
at any intermediate depth, by the rules and table we have 
already given ; but what we require is the mean velocity of 
the whole (heet of water. We could obtain this nearly by cal- 
culating the velocities for a great number of different depths, 
increafing by regular intervals, and taking a mean of the 
whole ; but we can effeft the fame with exaftnefs, if we take 
two-thirds of the velocity at the bottom, and confider it as 
the mean velocity of the whole body of water ; or, the ve- 
locity due to four-ninths of the depth, will give the fame 

In praftice we muft make allowance for lofs of motion by the 
friftion of the water in palling through the aperture, and alfo 
becaufe the water does not fill the aperture to the fame level 
as the ftagnant water in the refervoir. The motion of the 
water extends fome diftance into the refervoir, and the water 
will confequently have a Hoping furface from that part of 
the furface where the motion begins ; the flope will con- 
tinually increafe as the motion of the water accelerates, fo 
as to form a convex furface, which is a portion of a para- 
bolic curve; hence the furface of the water where it is In taking the depth, if it does not exceed four inches, it 
palling through the aperture will be in rapid motion, inftead of will not be exaft enough to take proportional parts for the 
being motionlefs as the theory fuppofes, and the furface will fraftions of an inch. The following method is exaft : if 
be much lower than the furface of the ftagnant water, fo there be odd quarters of an inch, look in the table for as 
that the aperture will only be half full of water ; at leaft this many inches as the depth contains quarters, and take the 
is the aftertion of M. Du Buat. But Dr. Robifon ftates, eighth part of the anfwer. Thus, for 3J inches take the 
that he always found the depth of the water in the aperture eighth part of 23.419, which correfponds to 15 inches, 
about .715 of the whole depth from the bottom of the aper- This is 2.927- 

ture to the level of the water in the refervoir. If the aperture is not in the fide of a large refervoir, but in 

M. Du Buat's theorem for the difcharge through an open a running llream, we muft augment the dilcharge, by multi- 
aperture, when reduced to Englifh mcafures, is this : having plying the feftion by the velocity of the ftreani. But this 
given the depth from the level furface of the water to the correiftion can feldom occur in praftice, becaufe in this cafe 
bottom of the aperture, and alfo the width of the aperture the difcharge is previoufly known. 

in inches, to find the difcharge in cubic inches per fecond. The amount of the allowance for friftion and lofs of 

Let it be remembered that 11. 4491 cubic inches of motion muft be different in different cafes, according to the 

water, or 1 i.j, will be difcharged in a fecond, through every kind of aperture, or board over which the water flows ; but 

inch in width of the aperture, when the bottom of it is ex- will always be very nearly the fame as the allowance, for lofs 

a£Uy one inch beneath the level furface of the refervoir. in an aperture or orifice of fimilar nature. For inllance, if 

To obtain the difcharge for any other depths, this number the edges of the aperture through which the water runs be 

muft be multiplied by the fquare root of the cube of the a thin plate, then we may find the velocity in feet per 

depth in inches, and it will give the cubic inches difcharged minute due to the whole depth from the bottom of the 

per fecond through each inch in width of the aperture. notch to the level furface of the water in the refervoir ; mul- 

Exomple. — Suppofe the depth of the bottom of the apcr- tiply the fquare root of the depth in inches by 85.87, as we 

3 have 

Cubic Feet <i;fch>r;e(l per Minute through each 

Dcpih from llit Bot- 

Inch of the Widili of the Apenur.. 

tom of the .\periure 

to ihe level Surface 

of the Water, in 

In fmall Aperiures of ( ,„ ^ Aperiuret 
Kfs than IS Indies ,,,,„ ^^ |,„.,,„, 





1. 1 40 

1. 211 

























1 1 










21. 117 















have before diredted, and take two-thirds of the produft for 
the mean velocity ; this multiphed by the number of fquare 
feet in the area of the feftion of the aperture, will give the 
cubic quantity of water which flows per minute in cubic 
feet. Note, in taking the area of the feftion, we muft meafure 
the whole depth from the level furface, and multiply it by the 
horizontal width of the aperture, and not fimply the feftion of 
the water. This is becaufe, the theory upon which the rule 
is founded fuppofes the water in the aperture to have no ve- 
locity at the iurface, and tobe upon the level of the Handing 
water. Neither of thefe fuppofitions is true in reality, 
but the refult is very nearly true, becaufe the feftion 
of the moving water is diminilhed in proportion to the ve- 

locity which the water has at the furface, and in confequence 
the errors of the two affumptions always correft each 

We have therefore only to apply a correft theorem to 
obtain the velocity due to the whole depth, according to the 
nature of the aperture, and take two-thirds of the produft. 
All the neceflary information for this purpofe may be taken 
from the table of multipliers lad given, for the velocity of 
the difcharge through apertures ; or otherwiie, if we take 
the velocity at the bottom, and multiply it by the depth, 
and take two-thirds of the produft, we fhall have the mean 
velocity. But to make the fubjeft clear we fhall give 
another table for this objeft. 

Rules for obtaining the Velocities and Quantities of Water difcharged tlu-ough reftangular Apertures, which are open 

at Top. 

Defcrlption of the Aperture. 

Wo(e. — The depths are fuppofed to be meafiired from the level furface of the wattr 
to the bottom of the aperture, in inches. 

To find ihe mean Ve- 
locity of the Water 

running through tlie 

Aperture in Feet per 

iJli/c — Multiply the 
Square Root of tlie 
Depth in Inches, by 
fome one of liie fol- 
lowin;; Numbers, 
according to the 

To find the Number of 
Cubic Feet difcliarged 
per Minute through 
each luch in Width 
of ihe ."Xperiure. 
K„/c. — Muhiply the 
Square Root of the 
Cube of the Depth 
In Indies; by foine 
One of the fullow- 
ing Numbers, ac- 
cording to the Cafe. 

For a fmall aperture in one fide of a large refervoir, the bottom"] 
and fides of which do not correfpond with the aperture, fo as to 
lead the particles of water thereto in a ftream ; the edges of the I 
aperture againft which the water runs is fuppofed to be (harp and 
made of thin plate; the aperture not to exceed i8 inches long 
and nine inches deep - . . . . 

For an aperture under the fame circumftances as the former, but! 
made in a plank with edges from half to one inch thick - -J 

For an aperture of great breadth and more than nine inches deep, 
fuch as the weir or dam in a river ; it is fuppofed that the 
water runs over the edge of a plank or walle board, one or tw 
inches thick - . . . 

For an aperture of which the bottom is on a level with the bottomT 
of the refervoir, or for a weir which occupies the whole breadth ( 
of a river, and where the water flows over the top of a broad f 
llone-wall fo Hoped as to conduft the water to the pailage -J 

For the full difcharge according to theory, fuppofing no lofs from 7 
friftion. Very large and deep weirs will come near to this -J 







When the aperture occupies nearly or the whole width of 
the refervoir, there is no level furface of the water above the 
aperture, becaufe the water is continually running towards 
the aperture in a ftream ; fuch is the cafe of a weir acrofs a 
river, or when water fpouts out of the open end of a reft- 
angular trough. 

It is extremely difficult to meafure the exaft height of 
the water above the bottom of the aperture, for the curva- 
ture of the furface of the water will begin feveral feet up 
the ftream before it arrives at the aperture ; and there muft 
be fomething arbitrary in the meafurement, becaufe the fur- 
face of the water, even where there is no curvature, is not 
horizontal but floping, when the water is in motion. In 
fuch cafes, the depth muft be taken beneath the inclined fur- 
face of the water, if we fuppofe the fame prolonged until it 
reaches the aperture, which can eafily be done, by ftretching 

a line along the furface of the water fo as to correfpond 
therewith, at the part above where the curvature com- 

We muft alfo make fome addition to the difcharge, on ac- 
count of the motion which the water poffefles before it comes 
to the aperture ; to do this with accuracy, we may meafure 
the regular velocity of the ftream, by throwing in floating 
bodies, and obferving the diftance they pafs through in a 
given time, taking care that we make this obfervation at a 
part of the channel, where the furface is in a regular motion 
and not in a ftate of acceleration, becaufe whai we want is 
the velocity of the water at that point where the curvature 
begins, in confequence of the defcent through the aperture. 
Now when the channel is not of an uniform breadth and 
depth, as in a mill-dam for inftance, the velocity of every 
part of the ftream is different, we fhall then find difficulty iij 



Refults of Thirteen Experiments on the Difcharge of Water 
through an Aperture open at Top, made by Meffrs. Smea- 
ton and Brindley, and M. Du Buat. 

Depth, in 
Inches, from 
the level Sur- 

Culiic Feet diCclnrged per 

Minute, nfcertaineJ bjr 


Cubic Feet di 

Minute by p 

Width, Maf 


[charged per 
ach Inch in 
oertsined by 

f»ce 10 the 

Bottom of the 



the Notch 

being fix 
Inches wide. 

by eith Inch 

by the Num- 

hy thcNuro- 


ill Width. 

ber .4031i4. 

b'cr .397 i4. 






1. 25 















* 1-778 















* 3-2 





• 4.665 




















* 6-753 





nieafuring the velocity by floating bodies, and muft apply the 
wheel ftream-meafiire before defcribcd ; this will give the pre- 
cife velocity of the furface at any given fpot, and we fhould 
choofe that place where the curvature begins. The velocity 
fo obtained we mull add to the mean velocity, and find the 
difcharge by multiplying the fum by the area of the aper- 

£*jm/>/(;.— Suppofe the depth of the bottom of the aper- 
ture to be eight inches beneath the line of the furface of 
the water ; that the width of the aperture is four feet, and 
that the aperture is in a thin plate with fliarp edges- Alio 
that the ftream is found by the wheel to move with a velo- 
city of thirty feet per minute, at the place where the furface 
of water begins to deviate from its regular flopc, and to af- 
fume a curvature. . 

Then take the numbers 57.246 from the firft cafe m our 
hft table, and multiply it by 2.83, which is the fquare root 
of eight (the depth) ; thus 57.246 x 2-83 = 162 feetfer 
minute, for the mean velocity of the water ; to this add 
30 feet for the previous motion = 192 feet /«r minute. The 
area of the aperture is 8 inches, or .66 feet x 4 feet = 
2.66 fquare feet. Multiply 192 feet velocity by 2.66, and 
we have 510.72 cubic feet per minute, for the quantity dif- 
charged. „■ j j 

Neater-Gauge for meafur'wg the Quantity of Water afforded 
by any Spring or Brool— The moll accurate and convenient 1 

method for this purpofe, is to conftruft a temporary bank , „ , r ,_ , , , , , r 

or dam to intercept the ftream, and pen it up into a pond, The two laft columns of the table are deduced from cal- 
then in the bank or dam fix a board with an aperture in it culation, and agree fo well with the obfervations as to give 
for the water to flow through. By meafuring the width and every confidence in the rules. The laft column is calculated 
depth of the aperture as before explained, the quantity can on the fuppofition that the aperture is made in a thin plate ; 
be calculated by the rules already given. but the laft column but one is according to Dr. Robifon'* 

This is what Mr. Smcaton called the water-gauge, and is number, and agrees more nearly with the truth. We believe 
of moft important ufe, to afcertain the quantity of water that Mr. Smeaton's experiments were made on an aperture 
which can be procured to fupply a canal, or for a town, or in a board one inch thick; the aperture was fix inches wide. 
a mill, or any other purpofe : it is the neceffary prelude for M. Du Buat's four experiments, denoted by * in the 
undertaking any fuch kind of work, and all perfons em- table, were in an aperture 184 inches wide, which we 
ployed in fuch purfuits, (hould underftand the manner of have reduced to fix inches, in order to compare them 
fixing up a gauge, and making the ncceftary obfervations. with Mr. Smeaton's. In making this comparifon, we 
The dam muft be of fuch a height as to pen up the water have not rejefted any experiment, as we were obliged to 
into a tolerable large pond compared with the aperture, fo do in the cafe of difcharge through the apertures beneatli 
that the furface of water (hall have no fenfible inclination or the furface. 

run towards the aperture ; and to avoid this, the larger the Self-regi/ierlng IValer-Gauge — When the produce of a fpring 
pond is the better. The water muft have fo much fall or ftream is required with great accuracy, the depth of the wa- 
down from the aperture, as to flow away in a clear ftream ter flowing througli the gauge muft be taken very frequently 
perfeaiy free from all obftruftion of the water below; but during a whole feafon, and a mean of all the refuhs obtained. 
it ftiould not fpout out fo as to fall far in the air. This would require the conftant attendance ot an intelligent 

The aperture ftiould be a reftangular notch cut in the perfon, and would be liable to miftakes ; but a fmall ma- 
edge of a broad plank ; it will be beft to make the length of chine may be made to flicw the depth by infpctftion, fo that 
the notch fome even number of inches, as 6, 8, 12, or 24, any careful perfon can keep the account. Thus, at the 
and the depth correfpondent to the quantity expefted to fide of the water-gauge, fix up a wooden or tin cylinder or 
flow through the aperture. trunk, which is open at the bottom, fo that the water can en- 

We recommend that the edges of the aperture be cut ter freely. In this trunk, or tube, let a float be placed, having 
fharp, or even faced with a flip of metal plate, and then a fmall light rod attached to the float that will rife up from 
our firft rule in the laft table will apply with great accu- it, and appear above the top of the trunk ; this part muft 
racy- The more common praftice is, to ufe a plank of one be divided into inches and tenths, and muft have fome 
inch thick, and leave the edges of the aperture of that index fixed to the trunk to read the divifions by- This 
thickncfs, only rounding off' the fliarp angles : in this cafe, apparatus muft be carefully adjufted ; in the firft inftance, by 
the fecond theorem in our table muft be f.fed ; but this is lefs the perfon who fixes the gauge, fo that its divifions will corre- 
certain, becaufe the lofs of motion from refiftance will not fpond with the depth of water meafured very cxatflly in the 
bear a conftant portion in diff"ercnt depths, for the thickncfs way we have direiHed ; then the float will ever after rife and 
of the plank is a conftant quantity, and therefore bears a fall with the furface of the water, and will fliew the depth 
different proportion to the quantity difcharged, in every without any necelTuy of referring to the original mode of 
eafc of a different depth. meafurement, unlefs it be to verify the adjullment- It ii 

The accur.icy of our rules, when applied to water-gauges, obvious that fuch an apparatus muft be fixed fo, that it can- 
will appear from the following tabic. not be deranged either by defign or accident. The tube 


in which the float afts ftiould be in the dill water fome feet 
above the plank in which the aperture is made, and have a 
proper box, or cover, which can be locked up, to fecure the 
whole. The float fliould be a hollow copper ball, or a glafs 
bottle, becaufe wood or cork floats abforb the water, and fink 
deeper therein ; and the rod of wood fhould be well painted. 
A ftill more perfeft water-gauge is obtained by a fmall ma- 
chine to keep the regifl;er ; for this purpofe, let an eight-day 
clock of the ordinary conftruftion be fixed up in a kind 
of centry-box, or fmall houfe, over the gauge ; this is to be 
connefted by wheel-work, with a cylindrical barrel, which 
is to be placed in a perpendicular direftion, and made to turn 
round once in a week by the clock ; a flieet of paper is 
wrapped round the barrel, and faftened upon it in the fame 
manner as paper is faftened on a drawing-board. 

The perpendicular ftem of the float muil haveafmall pencil 
attached to it, with a flight fpring to caufe it to bear againft 
the paper on the circumference of the cyhnder, fo as to mark 
upon it : in this way the pencil marks, at a different part of 
the length of the cylinder whenever the float rifes or falls, and 
the cylinder turning regularly on its axis by means of the 
clock, caufes thefe rifings and fallings to be marked on dif- 
ferent parts of the flieet of paper, fo that when it is removed 
from the cylinder it will have a curved line traced upon it, 
which flievvs all the increments and decrements of rife and 
fall, and affords an exaft regifter of the flow of water, 
which may be reduced to cubic meafure, by our rules already 

A different kind of water-gauge has been propofed by M. 
De Baader : two large cafks or other veffels are to be fixed 
Cde by fide, in fuch pofition, that the llream of water may 
be poured into either of them by a fpout or trough. The 
fpout is fo contrived, as to turn the ftream into one or other 
of the veffels at pleafure, with the greateft eafe, but the 
ftream cannot run into both at once. In each velTel is a 
large float which is connefted with a perpendicular ftem, 
fjo that the ftem rifes or falls with the float, as the veffels 
fill or empty ; alfo at the bottom of each velfel is a valve, 
or lluice, to allow the water to run out from it, and the 
perpendicular ftem from the float is provided with means to 
open this fluice, whenever the vefTel is full of water, and the 
float rifes to the top, or to fhut the fluice whenever the vef- 
fel is empty ; and the fame aftion turns the ftream of fupply 
from the veffel which is full, into that which is empty. In 
this way, the two veffels aft alternately to receive the water, 
and meafure it, for while the fpout runs into one veffel its 
float rifes until the veffel is quite full ; the float then turns 
the fpout and ftream into the other veffel, which we fup- 
pofe to be already empty, and at the fame moment it will 
open the valve in the bottom of the full veffel ; the water 
then begins to run out of the full veffel and to fill the other, 
which becoming full in turn, its float opens the valve in its 
bottom. In this way the machine continues to meafure the 
water, and is provided with a fmall counting machine to re- 
gifter the number of reciprocations it has made. 

We have now, as far as our limits will allow, given all the 
moft ufeful and praftical rules for meafuring flowing water ; 
and fhall conclude by obferving, that this is one of the moft 
intricate and difficult fubjefts in hydraulics, and that no en- 
gineer can be fully competent to direft the execution of large 
works without fludying the fubjeft much farther than we have 
been able to enter into it. Many untried cafes, and combina- 
tions of cafes, will continually arife, which cannot be decided 
by any previous knowledge. As a rsfource forfuch occafions, 
he fhould be well verfed in the theory of the fubjeft, fo as to 
modify the rules laid down for fimple cafes, and adapt them 
10 his particular cafe, as far as theory can affift him. 

If he only purfucs the rules laid down by others, without 
any knowledge of theory, and without entering into the 
reafon and origin of the rules, his experience will not be 
of much avail, becaufe he will be unable to correft and im- 
prove the rules by his own obfervations, or if he attempts 
to do fo, he may completely fpoil them, by making them 
falfe in many cafes, in order to obtain truth in fome one cafe. 
To attain the knowledge to which we allude, the follow- 
ing authors may be confulted. 

.luhus Frontinus, De Aciuxduftibus urbis Roms Com- 
mentarius; written about the year loo, in the time of the 
emperors Nerva and Trajan. This contains all the know- 
ledge of the ancients on this fubjeft. It is printed in 
Grsvii Thefaurus Antiquitatum Romanorum, vol. iv. 
1630 and 1780. A new edition was alfo publiflied. 

Caftelli, a difciple of Galileo, Delia Mcfura dell' acque 
correnti, 1628. 

Torricelli De Motu Gravium Naturaliter Accelerato, 
1643. I" this work we find the origin of the propofition, 
that the velocities of iff'uing fluids are as the fquare roots of 
the depths. 

Raphel Fabrettus de Aquis et Aqueduftibus veteris 
Romae, 1679. 

Marriotte, Traite du Mouvements des eaux, 1686. This 
work contains a great number of experiments on the motion 
of fluids, and particularly on jets of fpoutiiig fluids ; but 
the reafoning is frequently erroneous. 

Guglielmini, La Melura dell' acque correnti. — Alfo, 
Delia Natura dell Fuimi, Bologn. 1697. 

Guglielmini de Fluviis et Caftelhs Aquarum. Thefe 
contain a theory which has long fince been exploded. He 
firft attempted to apply the principles of faUing bodies to 
the motion of waters in open canals and rivers. 

Polenus, DeMotu aqus Mixto, Patav. 1697, 17 18, 1723. 
Parent Mem. Acad. Par. 1700. 

Newton's Principia, 1687. This work cont.iins the doc- 
trine, that the velocity of a fpouting fluid is equal to that 
which a heavy body acquires in falling through half the depth 
of the column ; but which is not correft. And in the fecond 
edition, 17 13, Newton firft points out the contrafted vein, 
and the proportion of its area to that of the orifice to be, as 
.707 to I. 

Polenus De Caftellis per quae derivantur fluviorum aquae, 
Padua, 1718. He ftates the area of the contrafted vein to be 
.571 of the area of the orifice, and he difcovered, that more 
water is yielded by a cyhndrical pipe than by a fimple 

Michelotti, De Separatione Fluidorum in Corpore Ani- 
male, 1719. 

Dr. Jurin, " On the Motion of running Water," pub- 
lifhed in the Philofophical Tranfaftions for 1718 and 1722. 
Lowthorp's Abridgment, vol. vi. p. 341. 

Raccolta De Autori che Trattano dell Moto dell' acque, 
3 torn. 4to. Florence, 1723. This moll valuable collec- 
tion contains the writings oi Archimedes, Albizi, Galileo, 
Caftelli, Michelini, Borelh, Montanari, Viviani, Caflini, Gug- 
lielmini, Grandi, Manfredi, Picard, and Narducci ; and an 
account of the numberlefs works which have been carried 
on, in the imbankment of the river Po in Italy. 

M. Couplet, Des Recherches iur le Mourement des eaux 
dans les tuyaux de conduit. Memoires de I'Acad. 1732. 
This is on the motion of water in pipes, and is given by 
Behdor in his Arch. Hydraulique. 

Architefture Hydraulique ou I'Art de Conduire d'elever 
et de menager les eaux pour fes differens befoins de la vie, 
in 4 vols. 4to. par M. Belidor, Commiffaire Provincial 
d'Artillerie, Paris, 1739. 



D.iniel Beraouilli, Hydrodynamica feu de viribus et 
niotibus Fluidorum Commentarii, Straft>ourg, 1738. He 
gives a beautiful mathematical theory. 

John Bernouilli fupported the fame theory in his Hy- 
draulica mine primum detefta et direft^ ex demonftrata ex 
principiis pure mechanicis. 

Maclaurin, in his Fluxions, Edin. 1742, has foHowed the 
fame traft. 

D'Alcmbert difputes the theory of Bernouilli in his 
Dynamics, 1743, and gives a new theory in his Traitc de 
I'Equilibrc et du Mouvement des Fluides, 1744, which he 
has farther improved in his EfTai fur la Refiftance des 
Fluides, 1752. 

Euler, in his Opufcules Mathematiques, has brought the 
theory of d'Alembert to perfeftion, 1752. 

Lecchi Idrotlatica efaminata ne fuoi principi e ftabilila 
nellse fue regole della mefura delle acque correnti, 1765. 

Nuova Raccolta di autori che trattano del moto dell' 
acque, 7 vols. Parma, 1766. This extenfive work contains 
the experiments and theorems of a vaft number of the pre- 
ceding authors on the fubjeft of running waters, the 
courfes of rivers, &c. Sec. and in a great meafure fuper- 
fedes all the Italian books of older date. 

Michelotti, Sperimenti Idrauliche, 1767 and 1774. — 
Alfo, Mem. Taurincns, 1788. This work contains a moft 
valuable feries of experiments made at Turin, fome of which 
we have quoted. 

Silberfchlag Theorie des Fleuves avec I'art de batir dans 
leur eaux et de prevenir leur ravages, 1769. Tranflated from 
the German. 

BofTut Traite Theorique et Experimental d'Hydrody- 
namique, 2 vols. 8vo. 1771, 1786, 1796. 

Du Buat, engineer to the French king, Principes d'Hy- 
draulique, 1779. His theory was firll founded on the ex- 
periments of Boffut and others ; but in 1786 he gave an- 
other edition containing many experiments of his own, and 
that valuable theory of the motion of water in rivers, which 
we have given in our article River, and which has made the 
firft. approach to accuracy. The honour of this difcovery 
is in part due to M. S. Honore, an officer of engineers. 

Dr. Robifon's Syftem of Mechanical Philofophy ; and 
the articles Hydrodynamics, River, Resistance, and 
VJ \TER-lVorii, which he prepared for the Encyclopa:dia 
Britannica. Thefe are the moft valuable coUeftion of 
experiments, theories, and praftical rules of any in the 
Enghfli language : the learned profefTor took the trouble 
to coUeft and arrange all the experiments of BofTut, Du 
Buat, and others, into one fyfteni. 

Ximenes, Nuova Sperienze Idrauliche fatte ne canali e 
nc fiumi per verificare Ic principale leggi e fenomeni delle 
acque correnti, Siena, 1780. Id. AA. Sien. iii. 16. iv. 31. 
▼ii. I. 

Lorgna, Memorie intomo all* acque correnti, Veron. 


Lorgna, Ricerche intorno alia diftributione delle velocita 
nella feAione de Fiumi. Id. Soc. Italian, iv. p. 369. 
V. 313. vi. 218. 

Dr. Matthew Young, Irifh Tranfaftions, 1788, vol. ii. 
p. 81. and vol. vii. p. 53. 

Prony, Recherchcs Phyfico-Mathematiques fur la Theorie 
des Eaux Courantes, 4to. Paris, 1804. This work con- 
tains a valuable coUeftion of experiments and theorems. 

M. Vcnturi of Modena, Recherchcs cxperimentales fur la 
Communication lateral du Mouvement dans its Fluides, 1 797, 
contains fome important difcoveries and experiments on the 
lateral communication of motion in Huids. It was tranflated 

by Mr." Nicholfon, in his 410. Philofophical Journal, 1798, 
vol. ii. and iii. It has been reprinted. 

Fabre, Surles Torrens et les Rivieres, Paris, 1797. 

Eytelwein Handbuch dcr Mechanick und der Hydraulik, 
Berlin, 180 1. This is principally known in England by 
the abftraft, publifhed by Dr. Young in the Journals of 
the Royal Inflitution, from which it appears to be a mofl 
valuable work. 

Dr. Thomas Young's Elements of Natural Philofophy, 
2 vols. Lond. 1807. 

Dr. Thomas Young's Hydraulic Inveftigations on the 
Friftion and Difcharge of Fluids running in Pipes, and of 
the Velocity of Rivers. ' Phil. Tranf. 1808. Valuable 
papers, of which we have largely availed ourfelves. 

Water, JVaght of. It is neceffary to afcertain the 
weight or abfolute gravity of fome known quantity or 
meafure of water with great precilion, becaufe we ufually 
exprefs the weight of different bodies by their fpecific 
gravity, that is, their relative weight to the weight of water. 
Hence, by knowing the weight of any required quantity of 
water, we may obtain the weight of the fame quantity of 
any other fubftance, by means of the fpecific gravity of 
fuch fubftance. 

It is recorded in the Philofophical Tranfaftions, N^ 169, 
that fome gentlemen at Oxford, in 1685, determined the 
weight of a cubic foot of fpring-water to be 1000 ounces 
avoirdupois. It was not obferved at that time that the 
denfity of water would increafe or diminifh according to 
the temperature. By a recent experiment by Dr. WoUaf- 
ton and Mr. Playfair, the cubic foot was found to weigh 
1000 ounces, or 625 pounds avoirdupois, at the tempera- 
ture of 56^ degrees of Fahrenheit. This we have made 
the foundation of the following tables. 
Tables of the Weights of different Quantities of diflilled 

Water, the Cubic Foot being afTumed 625 Pounds 

Avoirdupois, or 1000 Ounces, which is the cxaft 

Weight, when at the Temperature of 565° of Fahrenheit. 































































equal i ton 

A Prifni whofc 

Bafe is 1 Inch 



A Cylinder whofe 

Bafc is 1 Inch 


1 feet high 
6 feet high 
3 feet high 
I foot high 
1 inch high 








A Prifm 


A Prifm whofe 

A Cylinder whofe 

Bdfe is I Foot 


Bafe is 1 Foot 


I inch high 



I foot high 



3 feet higii 



6 feet high 



lo feet high 



20 feet high 



Weight of different Quantities of diftilled Water. 

Wine Meafure. 


Weight in 


Contents in 
Cubic Inches. 

Contents in 
Cul.ic Feet. 

A pint 

A gallon 

A rundlet - 

A barrel 

A tierce 

A hogftiead - 

A puncheon - 

A butt or pipe 

A tun 













1 1.229166 



Ale Meafure. 


Weight in 



Contents in 
Cubic Inches. 

Contents in 
Cubic Feet. 

A pint 

A gallon 

A firkin 

A kilderkin - 

A barrel 

A hogftiead - 











. .16319 

2.61 1 1 

Beer Meafure. 

Weight in 

Contents in 

Contents in 


Cubic Inches. 

Cubic Feet. 

A pint 




A gallon 




A firkin 




A kilderkin - 




A barrel 




A hogftiead - 




A butt 




Thefe tables ferve to afcertain the weight of any required 
quantity of any fubftance whofe fpecific gravity is known. 
Thus by our tables of fpecific gravities, in the article 
Gravity, we find the proportion which the weight of any 
required fubftance bears to that of water. Then to obtain 
the weight in pounds avoirdupois of any given quantity of 


fuch fubftance, multiply the number which expreffed the 
fpfcific gravity of the fubftance, by the number of pound* 
weight in the given quantity of water, as ftiewn by the pre- 
fent tables, and we have the weight of the fubftance in 

For example, it is required to know the weight of a 
piece of caft-iron, which contains feven cubic inches : the 
fpecific gravity of caft-iron, or its weight compared with that 
of water, is as 7.207 to i ; alfo by the above table we find 
7 cubic inches of water weigh .253 pounds avoirdupois: 
now multiply 7. 207 by .253 pounds, and we have 1.82337 1 
pounds weight for 7 cubic inches of caft-iron. 

What is the weight of a block of Portland-ftone, which 
is found by meafurement, to contain 9 cubic feet ? The 
weight of 9 cubic feet of water is by the table 562.5 
pounds, multiply this by 2.570, the fpecific gravity of Port- 
land-ftone, and we have 1445.6250 pounds for the weight 

What is the weight of a wrought iron bar, i inch fquare, 
and 10 feet long ? The above table ftiews that a prifm of 
water of that fize weighs 4.340 pounds, multiplied by 
7.788, the fpecific gravity of bar iron, gives 33.7999. 

In hke manner, if it was a round bar of i inch diameter, 
and 3 feet long, the fame table ftiews fuch a quantity ot 
water weighs 1,0226 pounds ; or, if it was a round plate of 
metal, i foot diameter, and i inch thick, the table ftiews 
the weight of its bulk in water is 4.090 pounds. 

The fourth, fifth, and fixth table is equally ufeful for 
commercial purpofcs, to determine the weight of different 
quantities of liquids, as wine, oil, fpirits, &c. 

Required the weight of an ale gallon of linfeed oil. The 
fpecific gravity of linfeed oil is .9403 ; the weight of an 
ale gallon of water is 10.1996 pounds, (as appears from 
the foregoing table,) multiply that number by .9403, and 
we have 9.5907, which is the weight of an ale gallon of lin- 
feed oil. 

What is the weight of a pipe of Bourdeaux wine ? The 
weight of as much water is 1052.73 ponnds, multiplied by 
.994, the fpecific gravity, gives 1046.4 1362 pounds. 

Oh the condufling of Water from a Dijlance for the Supply of 
To-wr.s. — This is a fubjeft of the utmoft importance, and 
involves much curious inveftigation. 

It frequently happens that the only fupply of frefti water 
for a town is from a diftant fpring, or that the quality of 
water which can be brought from a diftance is fo fuperior 
to the water on the fpot, as to induce the inhabitants to ex- 
pend vaft fums in procuring good water. The Romans 
were famous for their works of this kind, and many ruins 
ftill remain as monuments of the enterprifing fpirit of that 
people ; the moft celebrated of thefe we have mentioned in 
our article Aqueduct. 

The works of modern times are more numerous, though 
on a lefs fcale ; every great city has its water-works ; of all 
others, London is the moft plentifully fupplied. The New 
River, which condufts water from Ware, in Hertfordftiire, is 
a great work, which was executed in the reign of James I. ; 
fince that time a great many water-work companies have 
been eftabliftied, and moft of them draw their water from 
the river Thames by hydraulic machines. We believe that 
there are 1 6 large fteam-engines, befides the water-wheels at 
London-bridge, employed in this work, and almoft every 
ftreet has water-pipes laid in it. 

The city of Paris is fupplied by the Canal de L'Ourcq, and 
by three (team -engines ; but the pipes are only laid to the 
palaces and public fountains, and in grand houfes. 

Edinburgh is fupplied by water conveyed a vaft diftance 
Jl from 


from Comifton and Swan(lon> in leaden aud iron pipes ; courfe, wliich is a channel of ilone, and on each fide of it is 
but the fupply is very inadequate to the fize of the a narrow path with a parapet, whicli renders it fafe to wallt 
city. along the fide of the aquedudl when it requires cleaning or 

When water is to be conveyed in an open canal, like the repairing. 
New River, the manner of fetting out and executing the In the Philofophical Tranfaftions, it is ftated that this 
work is fo nearly the fame as for a navigable canal, that it aqueduft is 2560 fathoms in length, and confifts of 243 
is unneceflar)' to fay more than we have already given in arches ; the fpan of each is 6^ fathoms, and the thicknefs 
our article Canal, except the rules for calculating the ne- of each pillar to fuftain the arches 4 fathoms. On the fide 
C€flary flope or defcent to produce the required velocity of of the valley next to Maintenon, there are thirty-three fmgle 
the water; and the beft theorem for this purpofc we have arches, afterwards feventy-one double ones, (that is, having 
already given in the preceding part of the prefent article. one arch upon another,) then forty-fix treble ones ; at this 
We fliall only add a few particulars of fome of the largeft. part the water-courfe is generally 216 feet 6 inches high from 
modern aquedufts for conveying water. the ground up to the floor of the water channel ; afterwards 

yiqueduHs. — BeUdor ftates, in his Architefture Hydrauli- there are feventy-two double arches, then twenty fingle ones, 
que, tliat one of the fmell fubterraneous aqueduds in France which laft reach to a mound of earth, which is raifed 50 feet 
is that of Arcueil, which condufts the water from many high abo^e the ground for a great dillance. 
collefting channels in a ftone channel. It is fituated in the The general height from the ground up to the fecond ar- 
countries of Rungis, Paret, and Coutin. This aqueduft is cade or row of arches is 16 f.ithoms ; from the fecond row 
14,920 yards in length, and is conllrufted in free-done; it to the third or upper arcade 14 fathoms ; in the upper ar- 
cxtendsfromthevalley d' Arcueil to an elevated water-ciftern, cade, the arches arc double the number of thofe they ftand 
or chateau d'eau, which is at the Porte St. Jaques. The chan- upon ; above this is 6 fathoms 6 inches more to the floor of 
nel has an inclination of 6 inches in 400 yards, or i in 2400. the channel, which is at lead 7 feet high befides the pa- 

On each fide of the water-courie is a raifed foot-path rapet. 
lo inclics wide, upon which a perfon can walk as far as the The pillars at the ground are 8 fathoms thick, but with 
village d'Arcueil. The height of the paflage from the bot- the flopes and fhortenings, vvliich are made in every ftory ; 
torn of the water-trough to the under fide of the arch is 6f the top where the channel runs is reduced to 20 feet broad, 
feet, except in fome places where they have been obliged There is likewife at each pillar a buttrefs projefting one 
to make them lefs, in confequence of the high roads beneath fathom, and two fathoms wide to ftrengthen the pillars. 
which it pafles. There is another great aqueduft raifed on arches in the 

Another fubterraneous aqueduft of this kind is that of Plaine de Bue, which condudts water to Verfailles from the 
Rocquancourt, which conveys water to Verfailles ; it is Plaine de Scale. This is built with two ranks of arches, 
3623 yards in length, and in all the length has an inclination and the lower ones are fo much wider than the upper, as to 
of only 3I feet, which was the utmoft that could be given afford room for a carriage-way acrofs the valley about half 
it. To conftruft this aqueduft, they were obliged in many as high up as the water-courfe. Drawings of thefe great 
places to dig to a depth of 30 yards, whicii rendered the works are given by Behdor. 

execution of it very difficult. One hundred and fifty (hafts It is difficult to determine the exaft flope which fliould 
were made in the length of this aqueduft. They were not be given to a water-courfe, in order to conduft a given quan- 
made at equal diftances, but only in fuch places as would tity of water; it can only be known by calculation aecord- 
faciUtate the conveyance of materials ; eighty of them were ing to the rules we have already given, and which are founded 
lined with ftone, and the other feventy, which were not upon experience. Vitruvius recommended a flope of i foot 
required to laft longer than during the conftruftion, were fall in 200 feet in length ; but Belidor fays this is mucli more 
only lined with wood, and flopped up afterwards with a than is neccfTary, and that i foot fall in 3600 feet of length ia 
dome of mafonry, and filled up with earth to the level of the quite fufficient, when the channel is ftraight without elbows, 
furface. or fudden angles, or if the bends at fuch angles are by eafy 

This aqueduft coft 325,000 livres. From 1675 '° J678 curves, fo that the water is not retarded in changing its di- 
it never yielded more than 6 pouces of water, and fome reftion. He remarks, that the canal from the pool of 
times gave only 5, 4, 3, or even 2 pouces, according as the Trappes, made by M. Picard to conduft the water to Ver- 
dry feafons were of greater or lefs duration. The pouce de failles, had 9 inches Hope in 1000 fathoms, or i foot fall in 
fontainier is a meafure of running water ufcd by French en- 7998 feet long. When the water was run into this, it took 
gineers, which amounts to about .48 Englifh cubic feet four hours to run 8526 yards, though it was urged by a pref. 
per minute ; hence the 6 pouces would be 2.88 cubic feet fure of 38.3 inches. Alfo that the aqueduft of Rocquan- 
per minute. court before mentioned has only 3 picds fall in all its length, 

A pond was made in 1685 at the head of this aqueduft, which is 1 700 toifes, that is, i foot f.iU in 3400 feet of length, 
to drain a country called Trou d'Enfer; and fince then it Whence Belidor direfts as a general rule to make the fall 
Las given lo and 12 pouces, 't.e. 4.8 and 5.76 cubic feet ptr i inch in 100 yards, that is, i foot in 3600 feet, provided the 
minute. bottom of the trougli is of fmooth ftone, and not muddy. 

When water is condufted in an open channel, it fre- This is the leall which can be allowed, and more may be 
qucntly becomes neceflary to crofs deep valleys ; in this cafe, given when the relative levels between the two place s will 
the channel muft be fupported on arches like a bridge. Tliis admit of a more rapid defcent. 

was the objeft of thofe vaft Roman aquedufts, of which we On the Conveyance of IValer in Pipes. — Tliis is an objeft of 
find the remains at Nimes, Aries, Frejus, &c. The great- great importance. The ancients condufted water in pipes 
eft modern worksof this kind are thofe conftrufted in the time only down hill ; but never carried it up again, not knowing 
of Louis XIV. to conduft water to Verfailles and Marly, that water would rife to its own level ; but we can conduft 
One of thefe is the aqueduft of Maintenon, for conveying water to very great diftances, and bring it from one moun- 
the river Bure to Verfailles : it confifts of three courfes of tain to another in pipes, which defcend into the intermediate 
archcfl, raifed one above the other, to fupport the water- valleys and rife again, provided that the fpring or place from 



which the water comes is fomewhat higher than the other 
end where the water is to be delivered. The water would 
indeed fliew itfelf at the fame level at one end of the pipe as 
at the other, but it would not run out ; and in all cafes with 
the fame fize pipe, the quantity of water given will iiicreafe 
in proportion as the receptacle at the difcharge is below the 
fpring at the other end of the pipe. Hence, if there is a 
great deal of water to be conveyed to a place fituated but 
fittle lower than the level of the original fpring, a very large 
pipe muft be ufed to convey any given quantity. But the 
fame quantity may be conveyed in a fmaller pipe, and con- 
fequently at lefs expence, if the refervoir is much below the 
original level. 

If the diftance is great, the length of the pipes will con- 
fiderably diniiniih the quantity of water brought through 
them, in confequence of the friftion of the water againll the 
fides of the pipes ; this cannot be prevented, and we muft 
make the bore of the pipe larger, in proportion to the length, 
if the water be in fuch quantity and fo much wanted as to 
make it worth the expence. The rules for calculating the 
proper fize of pipes we have already given. 

Defaguliers mentions an experiment which he made upon 
a leaden pipe, whofe inward diameter was i| inch, and found 
that at 1400 yards diftance from the fpring of water that 
fupplied it, it did not give a tenth part of the water that it 
would have given at thirty yards from the fpring, though 
both places were at the fame depth below the furface. 

All care fliould be taken in the conftruftion of a conduit- 
pipe, to avoid obftruftions occafioned by lumps of folder hang- 
ing in the infide of the pipes, or by roughnefs at the joints, 
if the pipes are put together by fcrew-joints. All the cocks 
and plugs in the pipe (hould have water-ways fully equal to 
the feftion of the pipe. 

Thofe who execute water-works are moft tempted to fail 
in this point by making the cocks too fmall, becaufe large 
cocks are very expenfive. 

The engineer ihould be fcrupuloufly attentive to this, for 
a fingle contraftion of this kind may occafion the extra ex- 
pence of many hundred pounds in making a large pipe to be 
thrown away, becaufe if the pipe will yield no more water 
than can pafs through the fmall cock, it would have been 
as well to have laid a fmall pipe all the length. 

It is of the moft material confequence that there be no con- 
traftion in any part of a conduit, and it is alfo prudent to 
avoid all unneceffary enlargements ; for when a pipe is full 
of water moving along it, the velocity in every feftion muft 
be inverfelv proportional to the area of the feftion : hence 
the velocity is diminiflied wherever the pipe is enlarged ; and 
it muft agam be increafed where the pipe contrafts. 

This cannot be done without expending force in the ac- 
celeration ; and confuming part of tlie impelling power, 
whether it be that of a column of water, or the force of a 

No advantage can be gained by the flow motion which 
takes place at every enlargement in a pipe ; but every con- 
traftion, by requiring a reftoration of the former velocity, 
employs a part of the impelling force ; this force muft be 
equal to the weight of a column of water whofe bafe is the 
contrafted paffage, and whofe height is fufficient to produce 
that velocity with which the water muft pafs through the 

This point has often been overlooked by engineers of the 
firft eminence ; and has, in many inftances, impaired the per- 
formance of their beft works. 

Another point, which muft be attended to in the conduft- 
ing of water through pipes is, that the motion of the water 
fhould not be by pulfations, but continuous. When the 

water is to be driven along a pipe by the ftrokee of a reci- 
procating engine, it fhould firft be forced into an air-veffcl, 
that the elafticity of the confined air may preferve an uniform 
motion along the whole length of pipe. If the water is 
fuffered to reft at every fucceffive ftroke of the pifton, the 
whole mafs muft again be put in motion through all the 
length of the pipe. This requires a ufelefs expenditure of 
power, over and above the force which may be neceflary for 
raifing or conveying the water to its deftination. By employ- 
ing an air-veflcl and double or treble afting pumps we remove 
this imperfeftion, becaufe it keeps up the motion in the 
intervals between the ftrokes of the pifton. The com- 
preffion of the air by the aftivc ftroke of the pifton muft be 
fuch as to continue the impulfe during the momentary inac- 
tivity of the pump. 

Pipes are fubjeft to obftruftions from the depofition of 
fand or mud in the lower parts of the pipes, and from the 
colleftion of air in the upper parts of their bendings. The 
velocity of the water fhould always be very moderate, and 
then fuch depofitions of heavy matters are unavoidable ; 
care fhould therefore be taken to have the water freed from 
all impurities, before it enters the pipe by proper fil- 
tration ; and to difcharge the fecfiment which is unavoidable, 
there ought to be cleanfing plugs at the lower parts of the 
bendings, or rather a very little way beyond them. When 
thefe are opened, the water will ifTue with greater velocity, 
and carry the depofitions with it. 

It is much more difficult to get rid of the air which 
chokes the pipes, by lodging in their upper parts. This air 
is fometimes taken in along with the water at the refervoir, 
when the entry of the pipe is too near the furface ; but it is 
eafy to avoid this fource of the air, by making the water 
enter the pipe beneath the furface. For if the entry of the 
pipe is two feet under the furface of the water at the fpring, 
no air can ever get in, and a float may be placed over the 
entry, with a lid hanging from it to fhut the pipe before the 
water runs too low. 

Air is difengaged from fpring-water by the motion of the 
water in paffing along the pipe. When pipes are fupplied 
by an engine, air is very often drawn in by the pumps. It 
is alfo difengaged from its ftate of chemical union, when 
the pumps have a fuftion-pipe of ten or twelve feet, which 
is very common. In whatever way it is introduced, it col- 
lefts in all the upper part of bendings, and accumulates 
till it will choke the paffage, fo that fcarcely any water will 
be delivered. 

To illuftrate this, fuppofe that the water of a fpring, or 
colleftion of fprings, is to be conveyed through a pipe to 
the place of delivery, at a mile or half a mile diftant from 
the fpring ; and that the ground, over which the pipe is 
carried, has many undulations, and afcents and defcents, 
where it paffcs over fmall intermediate hills and valleys. 
We will fuppofe the place of declivity to be but a little 
lower than the water at the fpring, for example 9 or 10 
feet. If the furface of the water in the fpring comes down 
to the entrance-mouth of the pipe, or only near it, much 
air wiU run down with the water into the pipe ; and where- 
ever the ground rifes in the courfe of the pipe, this air will 
lodge itfelf in the upper parts of the bends of the pipe, 
and thereby diminifh the water-way fo as to force the 
water to pafs through a paffage of one-fifth or one-fixth, 
fometimes one-tenth of the proper bore of the pipe when 

Sometimes, though no air fhould get into the mouth at 

the fpring, there will be thefe lodgments of air from the 

firft runnmg of the water ; for when the water firft enters 

into the pipe, if after coming down from the fpring it has 

R s to 


to rife again, to pafs the fummit of a fmall hill, it will run 
over the eminence without carrying all the air before it, as 
it had done in other parts of the pipe, before it arrived at 
fuch eminence. Hence fome air is left in the higheft part of 
the bend, but the water which pafTes by the air runs forward 
and fills the pipe again in the dcfcending part, and fo goes 
on in a full bore, till it comes to the next eminence, where 
it again runs over the highell part of the rifing pipe, leav- 
ing a fpace of air at top, which dimini(hes the water-way. 
Then filling the pipe full again, it proceeds till its next 
rifing, and there the water-way is again contrafted by the 

To clear the pipe of this air, if the pipe is of lead, the 
common way, as praftifed by plumbers, is thus : at every 
rifing ground the pipe is laid bare at the higheft place, and 
a nail is driven into the upper fide of the pipe, fo as to make 
a hole through the metal. Whilft the nail is fticking in, the 
lead is hammered all round the nail, with the pen of the ham- 
mer, fo as to make a httle button or fpout. When the nail 
is withdrawn, the air will blow out violently, till at laft the 
water will fucceed the air ; and with a ilroke or two with 
the face of the hammer the hole can be quite ftopped up. 

This is done at every eminence of the pipe, until all the 
air is difcharged, and the full quantity of water will be de- 
livered at the oppofite end of the pipe. If the mouth 
of the pipe at the fpring never receives any air, by the defcent 
of the furface of the water, the pipe may give its full quan- 
tity for years. 

The way to know when the whole water is delivered is to 
meafure it, when the pipe has been fully cleared of air, as 
above-mentioned ; and when by meafure, tfie quantity of 
water appears to be deficient, the pipe muft again be cleared 
of air or other obftruCtions. 

If the fpring is much higher than the place of delivery, 
the places where the air will accumulate in the pipe will not 
be juft at the higheft part of the pipe, but a little beyond 
it ; becaufe the water running with more velocity and force, 
drives the lodged air ftill forward down the pipe, and it 
muft lodge in the part where the pipe begins to defcend 
again, its own tendency to afcend to the top being counter- 
aSed by the motion of the water. In this cafe, the nail-hole 
muft be made beyond the greateft elevation, or elfe the run 
of the pipe muft be ftopped for fome time, fo that the 
water may ceafe to be in motion, the air will then go back 
gradually to the higheft part of the pipe, where it may be 
let out. 

Suppofe that the water, inftead of coming from an ele- 
vated fpring, be forced up its whole way from a place much 
lower by an engine, and up the conduit, then t!ie places 
where the air will lodge will be beyond the eminences of the 
pipes, but nearer to the upper end. In thefe cafes, it will not 
be fufficient to prick the pipe with a nail, becaufe air will 
be continually forced in with the water, and will refill thofe 
places in the pipe from which the air had been emptied. 
The obftruftions thus happening often occafion the burft- 
ing of the pipe, or it gives too fmall a quantity of water, 
and does damage to the engine. 

In fuch a cafe, the following contrivance muft be ufcd : 
a fmall leaden pipe, about thirty feet in length, which is 
called a rider or air-pipe, is laid at the liighcft part of the 
main-pipe, and extends along the top thereof. It commu- 
nicates with the main at the top of the eminence, and alfo 
at two other places, at fifteen feet on each fide of the emi- 
nence. This air-pipe has a little branch and cock. Now if 
the cock is opened when the engine is working, the air will 
be puftied forward till it is difcharged by the air-pipe and 
cock. If the air goe« beyond the eminence, the pipe of 

communication will certainly difcharge it. When wBtei* 
comes out at the cock it muft be ftiut, and the main-pipe 
will then be full of water, but after fome time, the cock 
being left ftiut, air will gather again in the eminence of the 
main-pipe and lodge ; but, if the air-cock is again opened, 
the air will be difcharged. 

When water is forced up by an engine into an elevated 
ciftern, from which it is to run down a main-pipe to the re- 
fervoir where it is wanted, this air-cock will alfo be very 
neceflary, becaufe the water in the ciftern fomctimes covers 
the entrance-mouth of the defcending pipe, and fomctimes 
not. In that cafe, air goes down with the water. 

In leaden or iron pipes of conduit, the difcharge of air is 
abfolutely neceflary if there are any rifes in the pipe. In 
wooden pipes the air often pafles tlirough the wood an<f 
efcapes ; but if the pipes are tight and thoroughly foaked, 
the air-pipes and cocks are very ufeful. When water rung 
from a raifed ciftern through a diftance of a mile or two, 
fome perfon ftiould turn the air-cocks two or three times a 

This trouble may in fome cafes be avoided, by carrying 
the air-pipe perpendicularly upwards, to an equal or greater 
height than the entrance mouth of the main-pipe. In this 
cafe, the water will rife up in the air-pipe to near the fame 
level as the water at the entrance, but cannot run over. 
Neverthelefs, if any air paffes along the main-pipe, when it 
arrives at the air-pipe, it will rife up therein in bubbles 
through the water contained in the perpendicular air-pipe 
and eicape. By taking advantage of fome tall building, or 
large tree to fupport the perpendicular air-pipe, this e.K- 
pedient may in general be applied. 

Defaguliers contrived a valve which fliould open to let out 
the air, and fhut again when the water came. It was an in- 
verted brafs valve (hutting upwards, and faUing down by its 
own weight, with cork fixed to the under fide of it, to make 
it rife and fhut when the water came. This fucceeded in 
firft clearing the pipe of air, but it did not anfwer to keep 
it clear ; becaufe, when the valve had been ftiut fome time, 
if air (hoiild extricate itfelf from the water, it would be 
denfe air, whofe force would be equal to that of the water, 
and would keep the valve fhut as well as the water did be- 
fore, although the air at firft could not ftiut the valve. The 
only remedy for this difficulty is to make the valve very 
fmall, and make a hollow copper vcfTcl for a float. This 
will rife with confiderable force to ftiut the valve, when the 
water afls upon it ; and it will be fufficicntly heavy, when 
the water forfakes it, to pull open the valve. 

The fame author afterwards made a better contrivance. 
It is a fmall fquare box of caft-iron, made tight on 
all fides, except where the air-pipe communicates with the 
bottom of it, and alfo where a fpout is fixed on the top to 
let out the air. This fpout is provided with a cock, fitu- 
ated withinfide of the box, and to the plug of the cock a 
fmall arm or lever is fixed, having a hollow ball of copper 
at the extremity of the arm or lever. This ball floats on 
the furface of the water in the box, and when it rifes opens 
the cock, or fhuts it when it falls. When the air in the 
pipe accumulates, it paffes along the air-pipe and enters 
into this box, and as the quantity incrcafes, the furface of the 
water in the box fubfides, until the float at the end of the 
lever, opens the cock and allows the air to efcape, and this it 
will always do before any air can accumulate in the pipe. 

It is beft to place the air-box near to the main-pipe, but 
it muft have communication by an air-pipe with the main- 
pipe, at two or three dift^ercnt places, in order that it may 
certainly receive all the air which gathers in the great pipe. 

On the Difcharge of Water by lateral Branch-Pipes from a 



Main-Pipe.~~lt is a common cafe in water-works, that water 
is required to be drawn off through a fmall pipe, from the 
fide of a main-pipe, in which the water is not at reil, but in 
motion, with a much greater velocity than the flow occa- 
fioned by the water which is drawn off through tlie fmall 
pipe. It is often required to know what quantity fuch 
fmall pipe will yield. When water is pafling along a pipe, 
its preflure on the fides of the pipe is diminifhed in confe- 
quence of its velocity ; and if a pipe is derived from it, the 
quantity drawn off muft alfo be lefs than if the water in the 
great pipe was motionlefs. It is therefore of great im- 
portance to determine what is the diminution of pretTure 
which arifes from the motion along the main-pipe. 

It is plain, that if the water fuffered no refiftance in the 
main-pipe, its velocity would be that which is due to the 
height through which it had defcended, and it would pafs 
along without exerting any prefTure. Alfo, if the pipe were 
fhut at the eni^, the prefTure within the pipe would be 
equal to the whole depth of water. Between thefe limits we 
{hall find what we feek. If the head of water remains the 
fame as when the pipe was Hopped, and the end of the tube 
be contrafted, but not flopped entirely, the velocity in the 
pipe will be fmall ; and the natural velocity due to the 
defcent being checked, the particles will re-aft on what ob- 
ftrufts their motion. This aftion will be uniformly pro- 
pagated through the fluid in every direftion, and will 
exert prefTure on the fides of the pipe. Now obftruftions 
of any kind, arifing from friftion or any other caufe, will 
produce a diminution of velocity in the pipe. The refiftance, 
therefore, which we afcribe to friftion, produces the fame 
lateral prefTure which a contradlion of the orifice would do, 
provided that it would diminifh the velocity in the pipe, in 
an equal degree. 

We will firft confider the cafe of an horizontal pipe, in 
which the whole impelling force is applied at one end of the 
pipe, either by a pump or by a column in a perpendicular 
pipe at that end. This force muft be tranfmitted or carried 
by the water through the whole length of the pipe, wherein 
part of it will be abforbed in overcoming the obftruftion 
and friftion, and the remaining force will produce the velo- 
city with which the water ifTues at the open end of the pipe. 
It is evident that every part of the horizontal length of fuch a 
pipe muft bear a different degree of prefTure, when the water is 
in motion ; thus, at the end where it is difcharged, there is 
no prefTure exerted on the pipe to burft it open, becaufe 
the water can efcape freely ; but at every other part a force 
muft be exerted, which is fuflicient to overcome all the re- 
fiftance which the water will meet with, in running from fuch 
part to the open end, where it is difcharged. 

In fhort, whatever part of the column of water in the re- 
fervoir, or of the prefTure which impels it along the pipe, is 
not employed in producing velocity, muft be employed in 
afting againft fome obftruftion ; and by the re-aftion of this 
obftruftion, an equal prefTure is tranfmitted to all parts of 
the pipe. The chief queftions will be, in what part of the 
pipe are thefe obftruftions fituated, and at what part is the 
force applied which is to overcome them ; becaufe that part 
of the pipe which is between the two, muft bear the ftrain 
of tranfmitting the force from the place where it is applied, 
to the place where it is to operate. 

In the cafe where the impelling force is all applied at one end 
of the pipe, and the only refiftance is the friftion of the water 
in running through the horizontal pipe, the prefTure to burft 
the pipe, will begin at nothing at the open end of the pipe, 
and regularly increafe from that to the other end. Its quan- 
tity for 100 feet in length may be afcertained for any given 

bore of the pipe, and velocity of the water, from Mr. Smea. 
ton's table of friftion already given, and may be adapted to 
all other lengths by a fimple rule of proportion. 

If in addition to the refiftance by friftion, which takes 
place equally in all parts of the length of the pipe, there 
are any particular caufes of obftrudion at the extreme end 
or at any other part, the force necefTary to overcome fuch 
refiftance muft be added to that required to overcome the 
friction, as found by the table ; and all this tends to burft 
open the pipe, or that part which is between the impelling 
force and the obftruftion, which may arife either from a 
perpendicular column or lift, up which the water is to be 
forced, or from a contraftion. 

Example I — A fteam-engine with a forcing-pump is em- 
ployed to force water through a pipe, which proceeds hori- 
zontally for 1800 feet, and then rifes up 60 feet perpendi- 
cular, to a ciftern at the top of a tower ; the diameter of 
the pipe is five inches, and the motion of the engine is fuch, 
that the water moves with a velocity of 140 feet per minute 
through the pipe. It is necefTary to fupply a ciftern in a 
houfe from the middle of the mam-pipe, by a fmall branch- 
pipe of one inch bore and 100 feet long ; this ciftern is 55 
feet above the great horizontal-pipe, or five feet beneath the 
elevated ciftern ; required the velocity with which the water 
will flow through the fmall branch-pipe, when the engine is 
not at work, and when it is at work. 

When the water in the great pipe is motionlefs, there is 
the prefTure of a column of five feet to force the water 
through the branch-pipe. Mr. Smeaton's table fhews, that 
for one inch bore and 100 feet long, a prefTure of five feet, 
or fixty inches, will produce a veloc'ty of 1 80 feet per mi- 
nute ; but when this pipe is running, the water in the great 
pipe muft move alfo. The area of the pipe of five inches, is 
twenty-five times as great as the pipe of one inch ; therefore, 
the motion of the water in the great pipe, will be only one 
twenty-fifth of 180 feet, or 7.2 ieet per minute. Find the 
nearefl velocity to this in the table, or ten feet per minute, 
and under five inches bore, we find .07 inches the height ne- 
cefTary to produce that motion, if the pipe was 100 feet 
long ; but as it is 960 feet, the height required will be 
• 07 X 9.6 = .672 of an inch. This ftiould be dedufted 
from the five feet prefTure which urges the water through 
the fmall pipe ; but fo fmall a quantity is not worth notice : 
hence we may ftate the velocity when the engine is not at 
work at 1 80 feet per minute, and the difcharge from a bore 
of one inch, will be .98 of a cubic foot per minute. 

When the engine is at work, the fame prelTure will be ex- 
erted with the addition of all the prefTure necefTary to over- 
come the friftion of the water, in running along the great 
pipe with a velocity of 140 helper minute. Look for this ve- 
locity in the table, and for five inches bore it fhews, that a co- 
lumn of 7.6 inches m\ift be allowed for every 100 feet of the 
pipe. The length of the pipe meafured from the place where 
the branch-pipe proceeds to the ciftern at the top of the 
tower, is 900 feet horizontal, and 60 perpendicular, -viz, 960 ; 
therefore, multiply 7.6 by 9.6, and we have 73 inches for 
the height, which muft be added to the five feet, and makes 
133 inches for the whole column or force, which urges the 
water to flow through the branch-pipe, when the engine is 
at work : laftly, by referring to the table in the column of 
one inch bore, vi'e find that 135 inches will produce a velo 
city of 270 feel per minute, and the difcharge will be 1.47 
cubic feet per minute. 

The fame inveftigation fhews us, that the main-pipe at the 
place where the branch-pipe proceeds from it, muft bear the 
prelFure of a column equal to 66 feet one inch when the 



epgsne is at work, although it bears only 60 feet when it is 
at reft. But if we confidcr the whole length of i860 feet, 
the friAion will be equal to a column of eleven feet ten inches, 
fo that the prefTure, when the engine is at work, will be near 
72 feet, at that end of the pipe which joins to the pump. 

Exiimpk 2. — We will now confider the reverfe of this cafe, 
that is, takeaway the pump and fteam-engine, and let the water 
be propelled through the great pipe, by the water dcfcending 
from tlie cillern, with a fall of 60 feet. What will be the 
preflure which caufes the water to flow through the fmall 
branch-pipe ? 

To find this, we muft calculate with what velocity the 
water will flow through the whole length of the great pipe, 
by the theorem and example we have already given for 
water in pipes. Having found this, calculating on the 
whole length of the pipe, we muft make another calculation, 
reckoning only as much length of the pipe as is contained 
between the ciftern of fupply, and the place where the 
branch-pipe joins the main-pipe. 

Then take the difference between thefe two velocities, 
and it fliews what refiftance or friclion the water muft over- 
come in running along the remainder of the pipe, t'iz. from 
the place where the branch-pipe joins to the open end of 
the pipe, where the water is difcharged. Now if a fimple 
orifice was to be made at that part of the great pipe where 
the branch-pipe joins, the water would flow out with a ve- 
locity equal to the difference of the two velocities, making 
the proper deduftion for the friftion of the water in parting 
through the orifice. 

But if we wifh to know the velocity with which the water 
will flow through the branch-pipe, we muft find the depth 
of column neceflary to produce the velocity- equal to the 
difference of the velocities of which we have before fpoken, 
calculating according to theory, without regard to friftion ; 
and then with the depth fo found, we can feek in the table 
of friction in pipes, for the refult or flow of water through 
the fmall branch-pipe. 

The cafe of a regularly inclined pipe is confiderably dif- 
ferent,, becaufe the impeUing force is not all apphed at one 
end of the pipe ; but every portion of the pipe having a 
defcent, has alfo a portion of the impelling power applied 
to it. When this pipe is of a certain lengtli, the water 
arrives as its maximum velocity without accelerating as it 
proceeds further down the (lope ; becaufe the accelerating 
power of the water is in equiJibrio with the obftruftion, 
that is, the power of defcent acquired in a foot or an inch 
of the flope, is jull equal to the refiftance in the fame dif- 
tancc ; confequently, the water exerts no prefigure on the 
pipe to burft it open, any part of the water would continue 
to Aide down the flope with its uniform velocity, even if it 
was detached from that water which followed or which pre- 
ceded, and it derives no impelling power from any co- 
lumn of water. The effeft would be juft the fame, if 
the pipe was fplit down the middle and converted into two 
open troughs. 

It is clear, that in this cafe, no water can be obtained from 
any lateral branch-pipes, unlefs theydcfcend from the pipe. 

Let us confider the fame pipe when the inchnation is not 
a regular flope, but when fome parts flope more rapidly than 
others. In this cafe, the impelling force is not applied re- 
gularly upon every part of the length of the pipe, as in the 
tormer inftance ; the confeqnence is, that in thofe parts 
which have a more rapid flope than the inclination of 
a line drawn from one end of the pipe to the other, the 
water will have a tendency to accelerate beyond the regu- 
lar velocity which is due to the regular flope, and with 

which it muft ultunatcly flow out of the pipe ; and on the 
other hand, in places where the flope is lefs rapid than this 
line, the tendency of the water will be to flow more flowly 
than the regular velocity. Now the pipe being clofe and of 
an equal bore, the water muft flow with the fame velocity 
in every part of the length ; and although fome portions of 
the contained water tend to run forwards fader than the 
regular velocity, yet other portions tend to hang back ; 
by means of the pipe, the force is tranfmitted from one 
place to another, and thefe forces become all combined to- 
gether to produce an uniform velocity. 

We fliall find, on farther confidcration of thefe aftions, that 
fome parts mav be fubjefted to a prefture or ftrain to force 
or burft it open, and other parts may at the fame time be 
ftrained in an oppofite direftion, viz. to crufti the metal of 
the pipe inwards. 

Thus at every point where the pipe fuddenly changes its 
flope or rate of inclination, from an eafy flope to a very rapid 
defcent, then the water will have a tendency to run down fuch 
floping part of the pipe, and pafs away fafter than other 
water can come down the eafy flope ; the confequence is, that 
a fudion or afpiration takes place within the pipe, and if a 
fmall branch-pipe were applied in fuch a fituation, water 
may aftually be drawn up from a confiderable depth. This 
has been fliewn by M. Venturi, who calls it the lateral com- 
munication of motion between fluids. 

This is a certain proof that the bore of the pipe is too 
fmall at fuch places. An attentive confideration of thefe 
circumftances, will fliew the propriety of making a long 
pipe with different bores at different places, where the flope 
is different; for, by judicioufly increafing the bore of the 
pipe where the flope is lefs, the aftion may be made uniform 
throughout. But this cannot be done in cafes where the 
changes of flope are excefiive ; for inftance, when the pipe 
dcfcends rapidly into a deep valley, and muft rife again with 
a rapid flope in an oppofite direftion. This is the cafe with 
the pipes which fupply Edinburgh, and in many fituations 
is unavoidable. 

The refiftance arifing from friftion is greater or lefs ac- 
cording to the velocity of the motion ; but whatever is the 
inclination of a pipe, provided it is long enough, the velocity 
with which the water runs through it will fo adjuft itfelf, 
that the fum of all the refiftance in the whole length of the 
pipe, will exaftly balance the fum of all the forces, which 
the water exerts by its defcent. But if the pipe is 
too ftiort, the forces of defcent down the pipe may over- 
balance all the rcfiftances. In this cafe, the water will tend 
to accelerate, and the water which has dcfcended near to the 
bottom of the pipe, will draw after it that water which has 
juft entered the upper part of the flope, inllead of the water 
in the upper part, forcing forwai'ds that water which is 
beneath it. 

Dr. Robifon obferves that there are fome curious cir- 
cumftances in the mechanifm of thefe motions, which makes 
a certain length of pipe ncceffary, for bringing it into the 
equilibrium of motive force, and refiftance, which he calls 
trmn. A certain portion of the interior furface of the pipe 
muft aifl in concert in obftrufting the motion. AVe do not 
completely underftand this circumftance, but we can form 
a pretty diftincl notion of its mode of afling. The film of 
water contiguous to the pipe is withheld by the obftruc- 
tion of frietion, but glides along ; the film immediately within 
this is wiliihelJ by the outer film, but glides through it, 
and thus all the concentric films glide within thofe arou'nd 
them, fimilar to the tubes of a telefcope, when we draw it 
out by taking hold of the end of the innermoft. Thus the 
10 fecond 


fecond film paflcs beyond the tirft or innermott, and becomes 
the outermoft, and rubs along the tube. The third does 
the fame in its turn, and thus the central filaments will at 
laft come to the outfide, and fullain their greatell poflible 
obdruftion. When this is accomplifhed, the pipe is in 

This requires a certain length of pipe which we cannot 
determine by theory ; but it is evident that pipes of greater 
diameter mufl require a greater length, and this is probably 
in proportion to the number of filaments, or as the fquare of 
their diameter. 

Du Buat found this fuppofition agree with his experi- 
ments. A pipe of one inch in diameter hiftained no change 
of velocity by gradually fliortening it, until it was reduced to 
fix feet, and then it difcharged a little more water. But a 
pipe of two inches in diameter gave a fenfible augmentation 
of velocity, when (hortened to twenty -five feet ; he there- 
fore fays, that the fquares of the diameter in inches, mul- 
tiplied by 72, will exprefs the length in inches necefiary for 
putting the water in any pipe in train. 

When pipes are of any confiderable length, the waters of 
a larger pipe will run with a greater velocity than thofe of a 
fmaller pipe having the fame flopc. A pipe of two inches 
diameter will give much more water than four pipes of one 
inch diameter ; it will give as much as five and a half of fuch 
pipes, or more, becaufe the fquares of the difcharges are 
very nearly as the fifth powers of the diameters. 

On the requiftle Strength for IVater-Pipes. — We have {hewn 
that, in certain cafes, the water running through a pipe will 
exert little or no Itrain to buril the pipes. This may be 
the cafe in great portions of the length, or even in the 
whole length ; neverthelefs we may obferve, that at all parts 
fo fituated, an open canal would anfwer all purpofes as well 
as a clofe pipe. It is not neceffary to employ a clofe pipe 
in any cafe, except where it is fubjefted to a llrain. We 
may alfo obferve, that it is prudent in all cafes to make the 
pipe fufficiently ftrong to refill the full prefiure bf the im- 
pelling column, when the motion of the water is (lopped ; 
becaufe this may happen accidentally, and then the pipe 
will burft. 

In order to adjuft the ftrength of a pipe to the ftrain, we 
may conceive it as confifting of two half cylinders joined by 
feams, parallel to the axis or length of the pipe ; the 
ftrength of fuch feams to refift the feparation of the two half 
cylinders will be equal to the ordinary ftrength of the ma- 
terials of which the pipe is made. Theinfide prefture tends 
to burft the pipe by tearing open thefe feams, and the force 
which afts upon any given length of the pipe (as an inch or 
a foot), is the weight of a column of water whofe bafe is 
the diameter of the pipe, by the given length ( as an inch or 
a foot), and whofe height reaches up to the furface of the 
water in the refervoir. This follows from the common prin- 
ciples of hydroftatics, and may be calculated by the rules 
for columns of water already given. 

Suppofe the pipe to be of lead, one foot in diameter, 
what will be the force to burft open one inch in length, at 
the depth of 100 feet under the furface of the refervoir ? 
Water weighs 62^ pounds per cubic foot, the bafe of the 
column is i foot by i inch, or -^Vth of a fquare fojt, and the 
tendency to burft open an inch long of the pipe is 100 x 

62i X -rV = — — = 521 pounds nearly. 

Therefore, an inch long of each feam is ftrained by 2605 
pounds. A rod of caft lead, one inch fquare, is pulled 
afunder by 860 pounds. (See Strength of Materials.) 

Therefore, if the thicknefs of the feam is = — ~- inches, or 


one-third of an inch, it will juft withftand this ftrain. But 
we make it much thicker than this, efpecially if the pipe 
leads from an engine which fends the water along it by 

M. Montgolfier ftates, that a pipe one inch in diametee, 
and one line in thicknefs, will bear a column of 50 feet, 
French meafure, from which if we defire to know the 
proper thicknefs for any other diameter, with the fame pref- 
fure, we fliall find it by fimple proportion. Thus, if the 
diameter be 4. inches, the thicknefs muft be four fines ; or 
if the prelTure is augmented we pj-oceed in the fame man- 
ner, by direft proportion, fo that for loo feet it muft be 
two lines thick for one inch diameter, and 8 lines thick for 
4 inches diameter. 

To make full ufe of this mode of reckoning, he gives the 
following table of the preffure which pipes of different fub- 
ftances will fuftain. 

Copper pipe, i inch bore, and I line thick, will 7 

fupport a column of water - - - j 

Brafs pipe of good quality, and the former dimenfions 300 
Lead pipe, made of ftieet lead ... ^o 

Call -iron pipe, 2 inches bore, and 4 lines thick, will! 

fuftam at lead | 5°° 

Elm wood li inch diameter, and 2 inches thick, 30 or 40 

That is, tliey may fafely be made of that fize, but 
will bear fometimes 1 10 feet preffure. 

Lead Pipes. — The plumbers ufe caft pipes of lead, and 
alfo make pipes of tough fheet lead turned up, and burned 
or melted together in the longitudinal joints ; the different 
lengths of lead pipe are fometimes burned together with 
lead at the joints, when they are laid in the field, inftead of 
foldering, becaufe this is much cheaper. Leaden pipes may 
be turned up of any fize, but are not ufually caft of more 
than four inches bore. Unlefs the caft pipes are very 
found, they are not fo good as turned-up pipes ; hence it is 
not advifable to ufe caft pipes of more than 2^ inches bore. 
There muft be great care taken in making the turned-up 
pipes, that they may be perfeftly cylindrical. 

Small lead pipes are made by cafting and drawing them 
through a plate, like wire. See our article Pipes. 

The proper thicknefs for lead pipes, according to Defa- 
guliers, is as follows : a pipe, 7 inches diameter, fituated 
from 140 to 80 feet below the refervoir, muft be |- of an 
inch thick ; that part which is from 80 to 60 feet beneath 
the refervoir, muft be half an inch and an eighth thick ; from 
60 to 30 feet \ an inch ; and the remainder from 30 feet up 
to the refervoir f of an inch. 

For pipes of four inches diameter, half an inch will do 
from a depth of 200 feet to 100 feet ; from 100 to 40 feet 
depth I of an inch thick ; and from 40 feet deep up to the 
refervoir \ of an inch in thicknefs. 

Defaguliers defcribes a method of proving the ftrength 
of pipes experimentally, by a fmall forcing-pump, to injeft 
water into a piece of the pipe at one end, whilft a valve is 
applied to the other, which valve is loaded with fuch a 
weight as will equal the weight of the intended column of 
water ; therefore, if the pipe bears this preffure, it will bear 
the column of water. 

Lead pipes are very improper for water-works, where the 
water is forced by an engine ; for at every ftroke or pu/h 
from the engine, the water raifes the ftop-valve of the pump, 



and when the valve fliuts again, the water falls with it, and 
gives a fudden blow againft all the lides of the pipe. Bv 
the lateral prelTure, this force atls in a direAion perpen- 
dicular to the fides of the pipe, with the weight of a pillar 
of water whofe bafe is the feAion of the pipe, at the place 
of the ftrolce, and the height is equal to the whole height of 
the water above that place ; and it with the fame 
velocity that the valve falls. Now if the firfl ftroke of this 
water makes the lead fwell outwards but the looth part nf 
an inch, the lead having no elafticity, will remain in that 
pofition, and not (hrink back ; then fuppofe the next ftroke 
fwells the lead outwards the looth part of an inch more, the 
diameter of the pipe will become fo much larger and remain fo. 
The next ftroke will ftill make it wider, and fo on for many 
ftrokes, till at laft the lead becomes fo thin that it muft 
break. This is inevitable if the force is great enough to 
begin the enlargement, for after every ftroke the force of 
the water ftriking will be greater than the preceding, in 
confequence of the enlargement, and will foon burft the pipe. 
An iron pipe is beft to be ufed, for even if it were in itfolf 
as weak as the lead, it would not be liable to be enlarged, 
although each ftroke (hould make it yield, but by the 
elafticity of the metal it would return again to its own 
dimenfion after every ftroke. The fame will happen in 
pipes of copper or wood, becaufe thofe fubftances are 

Wood pipes are made of elm or oak, bored through the 
middle with a fucceffion of augres, increaling in fize until 
the defired bore is attained. Belidor fays a man can bore 
39 feet of elm pipe, two inches diameter, in a day, but only 
6^ feet of oak pipe. The manner of laying and joining 
pipes is fully explained in our article Pipe. 

Care muft always be taken that wood pipes are bored in 
the heart of the wood, and that the heart is of fufScient 
thicknefs about the bore of the pipe. Elm pipes of nine 
inches bore, that are from 80 to 140 feet beneath the fur- 
face of the water in the refervoir, muft have the heart of 
elm three inches thick after it is bored : therefore, a tree 
muft be chofen of no lefs than 18 inches diameter in the 
fmalleft part. For a depth from 60 to 80 feet, the heart 
muft be 2^ inches thick, which a tree of 17 inches in dia- 
meter will afford ; for a depth of from 30 to 60 feet, the 
heart muft be two inches thick, and the tree 1 6 inches in 
diameter ; and for any height under 30 feet, the heart need 
be but \\ inch thick, for which a tree of 14 inches will 

From thefe proportions it may be determined what thick- 
nefs the heai-t of elm ftiould be for pipes of lefs bore at the 
fame depths, taking it thinner in proportion to the diameter. 

Belidor recommends, in laying wooden pipes, to ufe a 
compoCtion of mutton fat beaten in a mortar with powder of 
brick-duft, fo as to make a fort of wax. When there are 
cracks in the wood, fmall wedges wrapped with tow, and 
covered with this compofition, are to be driven in to ftop 

Earthen Pipes — M. Belidor ftates, that the beft kinds in 
France are made at Savigny, near Beanvais ; they are in 
lengths of two feet, which enter three inches into one an- 
other, and are made of all diameters, from two to fix inches ; 
when the pottery is feven lines thick, they will bear a co- 
lumn of twenty-five feet of water. The joints are made of 
a compofition of pitch, afties, and brick-duft with mutton 
fat : this is applied hot ; but for laiger pipes, a cement of 
lime is ufed. 

One of the lengths of the pipes for the fupply of Edin- 
burgh is made of pottery. 

Iron Pipes. — The methods of joining and laying iron 
pipes will be found in our article Pipe; but we ftiall 
give a 

Table of the Weight of Iron Pipes caft at Carron Iron- 
Works in 1769, being their Standard for dried Sand 
Caftings, allowing every 36 Cubic Inches of Caft Iron 
to be equal to 10 lbs. 



of ihe 


of tL 

Thicknefs of 

Weight of the 

Infi'le, or 

of ihe Flancli. 

tl,e Pipe. 




Ft. In. 


Cwis. qrs. lbs. 





2 10 










I 10 







I 27 


1 1 


I I 18 





I 2 18 


I 2 



3 I 21 


■ 3 



* 3 3 20 


I 5 




6 10 


I 6 



6 3 4 


I 7 



7 I 22 

1 1 

I 9 



9 2 17 


I 10 



10 I 12 

1 '3 




II 26 

1 "^ 




II 27 

It v^'as afterwards found that, in a long courfe of practice, 
it was better to make iron pipes rather thicker ; becaufe in 
moulding there is fome uncertainty if the metal is equally 
thick all round. 

Water, Jels of, fountains were formerly the ornaments 
of all garden and pleafure-grounds ; but are now fo far out 
of faftiion, that we only find them in the gardens of the 
greateit palaces. 

The moft celebrated are thofe of Verfailles and St. Cloud 
in France, Frafcati, near Rome, and Peterhoff in Ruflia. 
The fubjecl of the latter is the conteft of Jupiter with the 
Titans ; it contains a column of nine inches diameter, which 
fpouts fixty feet high. 

The fountains of Verfailles, which are very numerous and 
magnificent, are fully defcribed by Belidor. 

They confift of four grand pieces, which contain excellent 
bronze ftatues, reprefenting fomc fubjetft of the mythology, 
befides a great number of jets for the ornament of fmaller 
pieces of fculpture. The bafon of Latona confifts of many 
jets, which throw up water obhquely 30 feet high, into tliree 
large bafons, from which it pours down in calcades. The 
water-piece of Neptune and Amphitrite confifts principally 
of perpendicular jets, which are very numerous. The bafon 
of Apollo contains the god in his chariot, drawn by four 
horfes ; the great jets of this piece rife 57 feet, and the fmaller 
jets 47 feet. The baths of Apollo contain moft excellent 
fculpture, and large (heets of water in cafcade. There are 
alfo the pyramids of water, mountains of water, alleys of 
water, theatre of water, &c. 

We have no room left for treating this fubjeft, which is 
of fome intricacy, and fliall conclude with Mr Mariot's 
table, which ftiews the altitude of a refervoir neceffary to 
produce a jet of a certain height ; and alfo the quantity ne- 
ceffary to fupply jets of a certain bore, mcafured in Paris 
feet and Paris pints, 42.36 of which are equal to a cubic 
foot EngPfftt. 


Quantity of 1 

Dianeter of 

Water Hifcliarged| 

the Con.luit- 

Altitude of 

Altitude of the 

n a Minute from 

Pipe, fuited 

the Jet. 


an Adjutage fix 

to tile 

Lines in 

two preceding 



Paris Feet. 

Ft. In. 

Paris Pints. 



S I 




10 4 




'S 9 




21 4 




27 I 








39 1 




4S 4 




5' 9 




58 4 




6s I 








79 « 




86 4 




93 9 




lOI 4 




109 I 

J 47 







125 I 




•33 4 



See our article Jet d'Eau, Vol. XVIIT. 

are very defirable, as being great additions to the beauty, va- 
riety, and embellifhrnent of them, when properly difpofcd 
and contrafted with feme nearly adjoining detached clumps 
of plantation, and bounded with a proper expanfe of grafs- 
ground, fpreading from the verge confiderably outwards. 
In general, when any fpaces of water, on a larger or fmaller 
fcale, are intended, they (hould be difpofed, as confpicu- 
oufly as poffible, in fome principal divifion ; either fometimcs 
at or near the termination of a fpacious open lawn, or occa- 
fionally in fome other fimilar open fpace ; and fometimea 
difpofed more or lefs internally, in fome central cr other 
grand opening ; in all of which an e-ipanl'e of water has a 
fine effeft. The particular forms may be adapted to the na- 
ture of the fituation, and the extent to that of the fupply 
cf water that can be had. 

In parks and pleafure-grounds, the moft proper fituations 
for plats, or other forms of water, are fome rather low con- 
venient places for containing and Supplying it, which are fo 
difpofed as to difplay an agreeable rural view of the water 
from the refidences and principal lawns and walks belong- 
ing to them, either near at hand, or at fome confiderable 
diftance from them ; and where there are occafionally other 
accidental fights and views of it, from other parts of the 
ground, unexpeftedly taking place in an abrupt or fudden 
manner. In thefe fituations the forms and appearances of it 
may likewife be greatly varied and diverfified, according to 
their particular nature and other concurring circumftances, 
fo as to take off any fort of formal regularity which they 
may have naturally. They may alfo have oval, oblong, 
winding, curving, or bending ferpentine direftions given to 

Water, in Gardening, a well known ufeful article in gar- them, as may be the moft natural and fuitable ; and they 

dening, as applicable to numerous forts of young plants and may be of fmall or very confiderable extents, in propor- 

trees, feed-beds, &c., efpecially in the droughty fpring and tion to the nature of the fituations, and the fizes of the 

fummer feafons, both fuch as grow in the full ground and grounds, as well as the fupplies of water which can be com- 

in pots in the open air, as well as thofe in green-houfes, manded. They are fometimes in large grounds, formed 

ftoves, hot-beds, &c. : and alfo in ornamental defigns, in in the manner of natural bending rivers or ftreamlcts, which 

pleafure-grounds, parks. Sec, either when formed into re- fweep round rifing fwells of land, planted with trees in the 

gular pieces, circular, oval, or in oblong or ferpentine ca- 
nals, &c.; likewife when varied in a fomewhat natural ex- 
panfe, in curves and bendings. 

In forming defigns of this fort, the nature of the fupply 

form of clumps, or other modes, fo as to produce a natural 
and agreeable effeft. 

Mr. London, in his ingenious work " On forming, im- 
proving, and managing Country Refidences," thinks that 

Ihould be firll confidered, whether it be by fprings in or water, in whatever point of view it may be taken, whether 

near the place, by currents or ftreams pafling through, or as neceffary to the produce of a country, the dehght of the 

fo nearly adjacent as to admit of being conducted to the traveller, or the intereft of romantic rural fcenery, is one 

place ; or by being condufted by fome neighbouring river, of the moft lovely ornamental materials of nature. Its 

brook, or lake, &c. by means of pipes or fmall cuts, or efFefts in all thefe ways are highly ufeful, interefting, and 

by being collefted ifluing from higher grounds, and con- beautiful ; without it all foils are barren and unproduftive, 

duAed by proper channels. And another circumftance, roads are dull and uninterefting to the tafteful traveller, and 

equally neceflary, is to confider the means by which it rural fcenes are often tame and difgufting. For as it occurs 

may be retained afterwards. In a loofe earthy, fandy, or gra- in fpringy banks, purling rills, or winding brooks, it 

velly bottom, it vnW foon fink away, efpecially in dry wea- equally engages and dehghts ; while in the more diilant 

ther, unlefs there is a conftant current or flow of water run- view, in larger expanfes, as thofe of great rivers, glaffy 

ning in ; but in a naturally ftrong clayey bottom, of pro- lakes, or the extent of the ocean, it exalts and fills the mind 

per thicknefs, both at the fides and below, it may be retained with aftonifhment. And in fecluded country fcenery it is 

in fome tolerable degree. In moft cafes, fome art, however, not lefs fuccefsful in affording variety and pleafure, either 

will be neceffary in this bufinefs. See Basons, &c. by the beauty of its varied appearance, the roar of its fall 

Where it is eafily attainable in any of the above modes, among rocks and cliffs, the foam and din of it in the fmall 

it fhould not be omitted, on a fmaller or larger fcale, efpe 
cially in grounds of any confiderable extent ; but where in 
tended principally as refervoirs for watering gardens, they 
may be of much more moderate dimenfions than when de 

cafcade, or the melancholy of it in the ftagnant pool, fhaded 
by over-hanging boughs. 

But though much has been ingenioufly and ufefully writ- 
ten on this interefting material of ornamental rural improve- 

figned for ornament, and may be formed either in a circular ment, and the necefTity and means of a better tafte inculcated 

manner, an oblong canal, pond, or cut, &c.; the ftiffnefs in the management of it, little alteration has yet been effeAi. 

of thefe forms being always broken by varying curves of ed in the modes of praftice, as few examples of artificial 

the margins or borders, conftantly forming them where the water rendered pifturefque have been fet before the public, 

fupply of water can be moft conveniently procured. The former old, naked, tame, fhaving, formal methods, 

Ornamental plats, or pieces of water in pleafure-grounds, ftill continue to prevail too much in the diftribution and 

Vol. XXXVIII. . S manner 


manner of condufting it. There are ftiH not a few who 
are infefted with 

that ftrange difeafe 

Which gives deformity thepower to pleafe : 

Colledtions of ornamental water may, it is faid, properly 
be confidered as of two kinds ; as thofe defigiied to be feen 
in a general view, and in conneftion with the adjoining 
fcenery ; and thofe to be feen only when near. The former 
forts chiefly confift of lakes, rivers, ponds, bafons, and 
^J;^^ of fimilar kinds ; the latter of fpriiigs, rills, rivu- 
lets cafcadcs, and Others of the fame nature. There are 
fcar'cely any fituations in which Wit^rs of the fpring, rivu- 
let, and others of the fame nature, may not be placed. In 
nature, rills arc ufually found deep funk in dells, as in :a- 
ftances where they run down the fides of hills, or pafs 
through foils of the fandy kind. Where they pafs through 
a fertile valley, or level meadow, they have commonly a very 
regular courfe ; and when they are met with in hollow 
places, their courfe is for the moft part ftraight, or ap- 
proaching to it. The fituations of rivers, lakes, and ponds, 
are almoft invariably in the lowed parts of the furface of the 
land. It is, indeed, impoffible that they could be other- 
wife. Water, whenever it occurs, is conttantly a ftriking 
feature in grounds, and in this way has always its pecuUar 
fituation : when that fituation is changed, every feature is per- 
verted ; truth, nature, and harmony, are fet at defiance, and 
the moft glaring difcord fubftituted in their place, ftriiing 
inftances of which prefent themfelves in many different or- 
namented fituations. 

The general Ihape of pieces of water muft depend upon 
the nature of the charafter which is to be created or given 
them. Whatever may be the magnitude or dimenfions of 
lakes or ponds, they (hould be of irregular (hapes, more or 
lefs wooded, and never entirely naked, being conftantly dif- 
tingui(hed by prominences and mafles ; and as often as oc- 
cafion may fervc, further varied by iflands managed in a 
fimilarity of manner. And the forms and direftions of 
rivers (hould be given by their fizes, and the nature and kind 
of country through which they are to pafs. Large rivers, 
in fertile plains, are, for the moft part, much lefs varied in 
their courfes than thofe of the fmallcr kind ; and both are a 
great deal lefs fo than thofe which have their direftions 
through hilly uneven furfaces, or through land of a rocky 
nature. Large rivers can never be imitated where there docs 
not exift a very confidcrable ftream ; as without this, the 
necedary degree of motion can never be given ; but the di- 
reftions or courfes of natural rivers may, it is fuppofed, be 
frequently altered, varied, improved, or divided, with the 
moft advantageous effefts in the way of ornament ; in all 
which cafes the remarks here given will be applicable. 
Much might be effeftcd in this way at many of the fine an- 
cient feats of this country, and a high degree of grandeur 
and magnificence of effeft be produced. 

In regard to the margins or borders of waters, and the 
accompaniments of them, it is fuggcftcd that there are two 
arguments or reafons, which clearly (hew that the former, in 
every piece of water, wliatever may be its charafter, fhould 
be broken and diverfified. The firft of which is, that there- 
by intricacy, variety, and harmony in form, colour, and 
difpofition, are produced, in the place of monotony or dif- 
cord ; the fecond is, that this mode prevails in nature. In- 
tricacy, variety, and harmony, are produced in the outline, 
by making the fmall parts irregular, confiderably fo in 
fome places, and lefs fo in others, according to the kind of 
water ; in the ground by producing breaks clofe to and 
alfo at forae diftance from the water ; by (hewing the naked 
or various-coloured earth aad gravel intcrfperfed among 

abruptnelTes, fmooth (lopes, levels, and by every form and 
difpofition of furface : it is further heightened by the in- 
troduftion of ftones of different (hapes, and placed in va- 
ried or intricate difpofition ; and alfo by roots, decaying 
trunks, or branches of trees. It is further fuggefted, 
that another fruitful fource of thefe beauties is plants, 
graffes, low growths, (hrubs, and trees. Plants and graffcs 
may, it is fuppofed, be employed both for cloathing fucli 
parts of the iurface as are fmooth, for varying others, and 
alfifting difpofition. Shrubs and trees may be ufed for the 
lail purpofe upon a more enlarged fcale. Plants, graffes, 
and low growths, give intricacy and fliade to fmall breaks, 
and the interilices among ftones, rocks, &c. Shrubs and 
trees give intricacy to large receffes, either of fimple mar- 
gin, or containing thefe leffer enrichments, which, (haded 
by trcCS; will be heightened in effeft. All this, it is fup- 
pofed, we fee sceompli(hed in nature in fuch a beautiful 
manner, as far furpalTea every fort of defcription ; it may, 
it is believed, be admired by penoRS of feeling alone, with- 
out much judgment or knowledge of the principles by 
which it pleafes or produces the effeft noticed ; but this 
kind of knowledge and judgment is highly ufeful in dircft- 
ing what to copy from nature, and how to apply it to arti- 
ficial pieces of water. Without it, perfons, it is contended, 
may argue either for copying the deformities or fingiilarities 
of nature, or for mifapplying them when copied, as has 
been done by feveral. There is a difference of charafter in 
the margin and accompaniments of a lake, river, and brook, 
though each is varied or harmonious. Each differs alfo ac- 
cording to the nature or ftyle of the country, or foil of the 
land through which they may have to pafs, as is evident from 
a great number of different inftances fcattered over the coun- 
try, in which there are particular differences in the banks, 
adjacent grounds, and accompaniments, that give an inte- 
refting variation of charafter to each individually. 

There are fome other ornamental appendages which are 
occafionally placed near to or upon water, fuch as ereftions of 
the bridge, and other kinds. There is no greater ornament 
to a piece of water of the nature of a river than a bridge, and 
few objefts fo generally plcafing, becaufe fo univerfally ufe- 
ful. This notion has been taken advantage of, it is fug- 
gefted, by improvers, but for the moft part in a very inju- 
dicious manner. Their bridges are too commonly formal, 
and uiiconnefted with the fcenery, either by their unfuitable 
magnitude, or by the loftinefs of their arches, ftraddling 
acrofs a (liallow liagnated river, as is the cafe in many well- 
known fituations. They want, it is contended, that beau- 
tiful fimplicity, conncftion, and pifturcfque effeft, which 
may be feen in many highway bridges acrofs ftrcams or 
rivers, and which is produced there by necejfity and time. 
Thus the arches, it is faid, are made low when the banks 
on each fide are tame and level, becaufe otherwife carts and 
carriages would have greater dif&culty in afcending them. 
The architefture is fimple, becaufe, in general, the builders 
were not allowed to incur the expence of ornaments. The 
plants, ivy-bufhes, and trees which group with them, have 
fpruiig up in the courfe of time, but they may be fpeedily 
imitated by art. The broken parapets, piers, or arches, 
fupplied by open railing, or a few pales, are the cffefts of 
time, or accident, and in fome cafes are worth imitating in 
the fcenery of a rcfidence. Thefe circumllances might 
eafily be copied in ornamental fcenery, and if judicioufly 
fupplied, it is faid, will invariably fucceed in producing a 
good cffe^. Fool -bridges of planks, or rude boles and 
trunks of trees, fuit well, it is fuppofed, with many fccn«» 
of the rural kind. Thcv have frequently been attempted, 
it is affertcd, but feldom with complete fucccfs, owing to 
the laftelcffncfs of thofe wlio contrived them. 



The other forts of ereflions whicii have been ufually em- 
ployed for the purpofe of ornamenting water, it is contend- 
ed, have rarely either pifturefque efFeft, or any ufe ; fuch, 
for inftance, as thofe of aquatic temples, Ilatues, river-gods, 
and other fimilar abfurdities, or what may be called falfe de- 
corations. Boat-houfes, however, of fimple conltruftions, 
and for the mod part all ufeful ibrts of ere£lio:is, may oc- 
cafionally be introduced with propriety and good effeft. 
The Perfian -wheel, the forcing-wheel, the corn-mill, and 
fome others of fimilar kinds, are had recourfe to with ex- 
cellent efFefts in different places. " The water-wheel and 
corn-mill at Warwick-caftle, it is faid, is perhaps the grandeft 
appendage to that noble building ; whether in refpeft to 
the train of ideas which it awakens in the mind refpedling its 
former compared with its prefent ufe, Ike, or its effeft in 
conneftion with the cafcade, for which it forms an excellent 
apology. And though cafcades of this kind be formal of 
themfelves, yet the idea of their utility, it is fuppofed, 
compen fates, in a confiderable degree, for the want of 
pifturefque grandeur ; and ftill the roar meets the ear 
through woods, or diftance, with the fame force as in thofe 
which are natural." 

Mr. London further fuppofes, that the piAurefque im- 
provement of the pieces of water which already exift will 
be attended to by all thofe who at prefent have artificial 
waters, in imitation of rivers, lakes, ponds, or brooks, 
and who are in the habit of making improvements of this 
kind upon their grounds. Such proprietors may, he 
thinks, be afTured that no part can Hand in greater 
need of alterations than fuch waters ; and fhould they 
go on with others, except planting, to the negleft of 
this, they will not certainly merit the approbation of men 
of tafte, as tafte always prefers excellence to quantity. 
" If, it is faid, any proprietor fhould hcfitate to alter a 
piece of water which he has long been accuftomed to fee 
without being fenfible perhaps of any great deformity, in 
confequence of habit, if he looks from his windows to a 
ferpentine river, winding among fmooth naked turf, with 
only here and there a few clumps placed at fome diftance 
from its margin ; if the water prefents one uniform glare of 
light, clear blue, or dull green, and feldom varied by any 
fliadows or refledtions but thofe of clumps and iky, let him, 
before he decides in favour of the tame river, imagine that 
in place of this a broad irregular lake, forming bays and 
receffes, retiring among thick woods, and with its margin 
in fome places abrupt, broken, and varied by ftones, plants, 
and creepers ; in one place fmooth, (loping, and covered 
with grafs ; and in another clothed with fhrubs, trees, and 
low growths ; then let him imagine ihat he fees thefe trees, 
woods, and the different coloured earths and ftones of the 
banks, reflefted upon the ftill furfaceof the water, which, in 
fome places, was covered with dark fhadows from the wood, 
and in others was bright and clear as the heavens : let him 
confider how interefting this would appear, even at a dif- 
tance, and how long he might be employed in tracing with 
the eye the various receffes, dark places, and refleftions, 
while ftill much remained indiftinCl or unfeen, and therefore 
either employed the imagination in completing it according 
to its own ideas, or awakened curiofity to walk down and ex- 
amine it minutely, by tracing, as far as could be done without 
the interruption of thickets and briars, the various windings 
and intricate margin of the whole. Let him only contrail 
this with the efFeft of the piece of water already there, 
which he c^n fee and knotu as completely by a fingle glance 
as if he viewed it an hour ; and could examine the two ex- 
tremities, which are all that could be difcovered by walking 
down to it, as completely in a few minutes as if he were to 

encompafs it a whole day. If the centratt does not llrike 
him, he certainly, it is contended, as far as regards his own 
tafte, is juftified in preferving his water as it is ; but if 
otherwife, he ought to commence improvement immediately, 
not only in gratification of his own fentiments, but alfo in 
juftice to every attempt to promote and introduce good tafte 
in a country where he is a proprietor, and among a people 
upon whom he is dependent for his rank and affluence. 
Different ftyles of improvement may, it is obferved, be or- 
namental, and admired while they are in faftiion ; but it is 
only fuch as this, which are pifturefque, or natural, that 
can ftand the teft of time." 

The firft thing to be confidered in the alteration of artifi- 
cial pieces of water, is the charafter which ought to be 
adopted ; and the next, the execution of that charafter in 
the bell manner poffible, and with the leaft expence of 
libour and money. The former has been already fully no- 
ticed, and the latter will be particularly confidered below. 
In many cafes, however, the alterations required are fo very 
fimple, as to ftand in need of little art, either in the defigns or 
the praAical parts, as has happened in altering the waters of 
different fine country-feats. 

In ftiort, the management of natural pieces of water, 
where they come within the province of pifturefque im- 
provement, moftly confifts in rendering them more charafter- 
iftic, and by the occafional introduction oi particular effeds. 
The leadmg principles in effefting the firft of thefe im- 
provements have been made fufiiciently obvious already ; and 
the latter are derived from what takes place in nature ; as 
in the cafes of waterfalls, cafcades, fpnngs, and droop- 
ing banks or rocks, on the margins of large brooks or 
rivers, all of which may, it is fuppofed, be imitated in parti- 
cular inftances. Alfo, in rills and fmaller ftreams there 
are dank pools, ponds, and little lakes, which often occur 
in their courfes, that are highly worthy of imitation for 
their intrinfic beauty, their contraft with the narrow rills, 
and their ufe in landfcape. Belides, it is fuggefted that a 
great advantage of fuch pools, or little lakes, is, that they 
may be made to appear natural where no other variety of 
ftill water could poilibly be attempted. And that, in nature, 
they are found on the fides of dechvities, where they are, 
for the moft part, covered by wood, and feen only on a 
near view. In level places or fituations, or fuch furfaces as 
are not ftrikingly inclined, they are or may be opened in 
fome parts, for the purpofe of being feen from diftant 
places in the grounds, as is admirably done in fome 

Another fort of occafional appearance or effeft is 
tjlandi, and they are particularly deferving of imitation, 
eipecially in lakes and ponds ; nay, even in large rivers or 
brooks they have often a good effeft. In large rivers they 
are moftly long and narrow ; and in brooks frequently fo 
large as to be wholly out of proportion to the ftream, 
containing much extent of furface ; but fometimes th ey ar 
extremely fmall, and only contain a fingle buih, a few 
bulhes, trees, or ftones and plants ; each of which cafes 
may be feen in almoft every brook, and they deferve imita- 
tion. Iflands in ponds, it is fuppofed, fhould rather be nu- 
merous and near together, than large and diftant, and be 
fituated rather approacliing the fides than the middle parts ; 
the apparent magnitude of a piece of water may, it is fug- 
gefted, be greatly heightened from the main point of view, 
by placing moft of the largeft iflands next the eye, as well 
as by the mode of planting them. In regard to planting 
iflands in general they ihould be wooded, but not wholly, 
and never in fuch a way as to exclude the appearance of 
furface, broken ground, rocks, roots, and ftones, which 
S 2 are 


are more, natural lo iflands than to (hores, becaufe it muft 
always be fuppofed that it has been fome of thefe ma- 
terials which have either occafioned the accumulation of 
the idand, or prevented it from being wafhed away after- 

Waterfalls and cafcades are alfo occafionally introduced in 
eKtenfive plcafure-grounds, where there is the advantage of 
a rivulet, by which they may be formed cither in one large 
fall, or in two or three fmaller ones in fucceflion, having 
large rough ftoncs placed below to break the water, and in- 
creafe the found of the torrent in its fall and paffage over 
them, in fome degree fimilar to that peculiar to natural caf- 
cades. And fountains, fpouting water from images, S(.c. 
are fometimes introduced in the centre of fmall or moderate 
bafons, or other refervoirs of water in gardens or grounds, 
where a fupplyihg head of water is conveniently fituated 
fufficiently high to raife and throw the water from the jet 
orfpout, in a continued full ftrcam, to a confiderable height, 
which falling in the bafon, keeps the water of it in motion, 
prevents ft agnation, and is thereby rendered more proper for 
keeping and breeding fifh of the gold and Clver kinds, &c. 
and the fpouting and falling of the water have a refrefhing 
efiFeft in the heat of fummer. In parterres, Ihrubbery 

f rounds, and particular kinds of gardens, water is intro- 
uced either in the forms of ftill ponds, drooping fountains, 
or jets d'eau ; but as thefe are all artificial, no perfeft 
mode can be afforded for imitation. They, however, mod 
of them proceed in fome meafure on the principle of con- 
trail, which, in every modification of matter, is capable of 
producing either incongruity, variety, or harmony ; confe- 
quently, of effecting fcenes which fhall difgult, pleafe, or 
highly intereft the beholder. Jets d'eau are not at prefent in 
fuch difrepute as they were formerly in this country ; but 
they are, for the moft part, lefs underftood, and their pro- 
per ufe lefs comprehended. 

Mr. London, in the above work, remarks, that the epi- 
thets waterfalls and cafcades denote different cliarafters in or- 
namental improvements. Where the water falls over a ridge 
of rock in one or Taorejheets, they are properly denominated 
waterfalls ; and where its fall is broken and interrupted by 
the irregularity of the ridge, and by other fragments of 
rocks and ftones, they are properly cafcades. Both kinds, 
it is fuggeiled, may be imitated in improved fcenery, though 
hitherto this has fcldom been well accomplifhed, on account 
either of the reftrifted praftical knowledge of perfons of 
tafle, or the limited or vitiated tafte, or deficiency of judg- 
ment, in thofe who have had the neceffary practical expe- 
rience in matters of this kind. 

However, waterfalls may either, it is fuppofed, be imi- 
tated direftly, by being copied from nature, or indireftly, 
by the introduftion of weirs for the ufe of water-mills, as 
already hinted. In imitating nature, thcjlrength or durabi- 
lity of the whole mufl be equally taken into confideration 
with that of the beauty. Thcfirft depends upon the gene- 
ral form of the whole materials, and the fecond principally 
on the foundation ; but in a partial way alfo, on the quality 
of the materials, and the execution. In every cafe which is 
upon a large fcale, the foundation ought to be the natural 
rock, if polTible ; but on a more moderate or fmall fcale, 
it may be a fecure caufeway, fixed by oak piles and crofs- 
planks, the work being performed with great care, and in an 
exafl manner ; ufing fuch mortar, where necelTary, as is ca- 
pable of refilling water. 

It is noticed, that there is one variety of waterfall which 
may be occafionally fecn in nature, and which is highly 
worthy of imitation, though it is not known to have ever 
yet been attempted to be introduced. It is that where a 

fmall rivulet or rill, at its junAion with a river or brook, 
falls over a rock in one fmall (heet. It is flated that, " at 
Matlock Bath, the noife of a fmall waterfall of this kind 
forms one of the fineft circumftances of the fcenery about 
that place ; — borne upon the breeze, its grateful harmony 
meets the ear in almofl every part of the adjacent fcenery, 
in murmurs as varied as their paffages through woods and 
open glades, along the furface of the Dove, under the 
echoing cliffs of the Tor, or afcending the heights of 
Abram. This remarkable effcft, it is contended, produced 
by fuch a fmall quantity of water, ought to be the greateft 
encouragement to fuch as poffefs brooks or rivulets, as few 
cafes can occur where it may net be imitated ; not indeed 
with fuch remarkable fuccefs, becaufe the furrounding 
fcenery may not be fo varied, but ftill with fuch an effect as 
would amply compenfate for the expencc, which in every 
cafe could be but trifling." Others are fuggefled, and the 
beft manner of forming them clearly explained by drawn 

The nature of waterfalls for the purpofe of driving ma- 
chinery are, it is obferved, generally pretty well under- 
flood ; and that as no difguife in the mafonry is requifite, 
but art is commonly to appearj the principles of ftrength 
and durability noticed above are what chiefly demand atten- 
tion. But it is remarked that it is to be regretted that fo 
few who have rivers take advantage of it, and that fo many 
make cafcades equally formal and unnatural, without any 
real ufe, and with little beauty, either of charafter in them- 
felvea, or fitnefs and conneftion with the fcenery about 

As to cafcades, what has been faid in refpcft to water- 
falls will in general apply. In thofe which are upon a fmall 
fcale, and where there is a plentiful fupply of water at all 
feafons of the year, the fame forms may be built with fimi- 
lar care in refpeft to foundation, folidity, and mortar, they 
being then difguifed by rocks of different fizes in a natural 
manner, in different wavs, according to the different circum- 
ftances of the places. The fame general principles in relation 
to form will be applicable to all kinds of hearts, fifh-ponds, 
&c.; only in thefe cafes the materials are commonly clay or 
gravel ; which laft fhould always be well pudJUd with clay 
or ftiff loam on the fide next the water. In defigning 
waterfalls and cafcades, one principal confideration is, it is 
faid, to adapt them properly to the fcenery. In fome cafes, 
they are quite inadmiffible, as in all rivers or brooks without 
ftones or rocks in their beds or margins ; and in others 
where they are few, or where the ground on each fide is 
level, they can never be made of any great magnitude. An 
attention to nature is, however, fufficicnt to guide us in 
this, as well as in every thing elfe which relates to the fub- 
jeft ; a fubjeft which, it is faid, is fo highly interefting and 
comprchcnfive, that it would require a very great fpace to 
give a complete elucidation of it in every refpeft. See 
Vf KTKK-FaUi. 

It may be noticed, that in the bufinefs of forming gpround 
for water, the earth muft be excavated to a proper depth, gra- 
dually Hoping from the verge to the middle, from three to four 
or five feet deep ; fometimes, however, in low fituations, the 
place is naturally hollowed in fome degree, fo as not to re- 
quire a general excavation, or only in particular parts, and 
fome general regulations to the whole, which in extenfive 
defigns is a confiderable advantage. Where the fides and 
bottom are of a fandy, gravelly, or ftony nature, or abound 
in loofe foil, and there is not a conftant fupplying ftream, 
tliey muft be well fccurcd by the application of a thick coat 
of well-wrought clay. And where this claying is neceffary 
in the preparatory excavation, a proper allowance fhould be 



made for the additional coat of clay, to the extent of twelve 
or fifteen inches in thicknefs, and of feveral inches of gravel 
over it, to preferve the clay from being wafted by the mo- 
tion of the water, and keep it clear, which would otherwife 
be muddy. But previous to the claying, the loofe and 
uneven parts in the bottom and fides of the cavity Ihould be 
well rammed, to make the whole firm, even, arid fmooth ; 
then beginning in the middle fpace with the clay, and pro- 
ceeding gradually outward, being careful that no ftones, 
ilicks, or other matter, get mixed with it, to occafion fif- 
fures, or cracks, by which the water may efcape, laying it 
evenly, a fmall thicknefs at a time, and fpreading it regu- 
lacly, treading it well with the naked feet ; and if dry 
weather, carting water on it oecafionally, ramming it well 
from time to time with wooden rammers ; then gradually 
applying more clay, in the fame manner, to the proper 
thicknefs, being careful that every part is fo well puddled 
and rammed, as not to leave the fmalleft vacancy. Thus 
continuing the claying in a regular manner each way, from 
the bottom to the top of the circumference, fmoothing the 
furface evenly, and m dry weather covering it, as the work 
proceeds, with matts or ftraw litter, or with the llratum of 
pebbly gravel. When the whole is finifhed, the water 
ftiould be let in. 

When this has been done, the top or verge muft be regu- 
lated and levelled, forming it evenly from the edge of the 
water, in n gradual regular expanfion to fome extent out- 
ward, without any ftiff flope clofe to the water, diftinft 
from the furrounding fuperficies ; laying the ground with 
grafs turf, efpecially along the margin, continuing it as far 
down as the general level of the water. Where the extent 
is confiderable it may be fown with grafs-feeds. 

In conftru6ting the excavations for a body of water in 
fuch fituations as are deficient of materials in fome of their 
parts, as too low in fome of their boundaries, as either at 
the ends or fides finking below the general furface of the 
ground, or the height at which the water is intended to 
iiand ; thefe parts muft be ftrongly banked up to the ne- 
cefTary height in a fubftantial manner, having a fufficient 
body of proper materials applied, efpecially where the part 
is to form a head at the end of a canal, or other fimilar 
piece of water ; the whole being inwardly faced with a 
ftrong body of well puddled clay. 

It is well known by every one, the above writer fays, 
that the expence attending the formation of artificial water 
by the modes whicli have hitherto been chiefly praftifed is 
enormous, and in fome inftances icarcely fupportable ; but 
by adopting improved methods, fuch as thofe which have 
been fuggelted, it will in almoft every cafe be greatly re- 
duced, and become much cheaper, often to a very remark- 
able degree. This will be rendered quite evident by con- 
fidering the different necelTary operations in their formation, 
as they relate to each method of proceeding ; fuch, for in- 
ftance, as the excavation of the bed for the water, the form- 
ation of the head, the fpreading of the earth taken out, and 
the management of the furrounding furface. In regard to 
the firft, the principal reafon why it becomes fo expenfive 
is, that a river is commonly imitated inftead of a lake, which, 
on account of the natural Hope of all grounds, requires not 
merely larger heads, but a far greater number of them. 
By in a great meafure imitating lakes, one head is, for the 
moft part, all that is required ; and this alfo, many times, 
of a far fmaller dimenfion than thofe in the cafes of rivers. 
This alone often makes a very material difference in the 

In what relates to the fpreading of the excavated earth, 
and the regulation of the furrounding furface, as in the me- 

thods hitherto purfued in landfcape gardening, whatever 
may be the natural charaAer or tendency of the furround- 
ing furface, it is to be reduced, by levelling, to a fmooth, 
even lawn, or pafture. Hoping in a gradual manner firom 
the margin of the water. This of courfe caufes a prodi- 
gious expenditure of money ; and what is ftill more dif- 
agreeable, it is too frequently quite uncertain, and only 
capable of being calculated after the finifhing of the whole 
work. The quantity of cubical yards to be removed in the 
work of excavating 'can be eftimated very nearly to a cer- 
tainty ; but the bufinefs of levelling is intricate, trouble- 
fome, and often of great extent ; hence the great excefs of 
expence which is frequently incurred beyond the eftimate in 
this refpeft in pieces of made water. If any one plan ever 
had the advantage over another, it is contended that certainly 
pifturefque or natural pieces of water have the full and 
complete fuperiority over thofe of other kinds in what re- 
gards expence. In them, it is maintained, the natural cha- 
rafter of the ground is preferved or improved, and confe- 
quently no expence of leveUing is incurred ; the fuperflu- 
ous earth produced in the procefs of excavating being 
formed into irregular inequalities, or diftributed along the 
banks in fuch a manner as to augment or increafe their cha- 
rafterandpidl;urefquenefs,as is evident in numerous inftances. 
Under other circumftances, vaft expence may often be run 
into, without much, if any, beauty being produced ; when 
it could have been effefted to a great extent by the modes 
which are here advifed without laying out much money. 
Farther information on this very interefting fubjedl may be 
gained by confulting Mr. London's excellent work. 

Water, Rain, Collealng of, for Farm Ufe, in Rural 
Economy, the providing it in proper fituations for the 
purpofe. This praftice was formerly adopted in different 
parts of the country : as in moft towns, and in the yards, 
ponds for the ufe of cattle, are ftill to be met with, which 
have an artificial appearance. In extenfive pafture heavy 
or about the houfes of many old farm-lands, pools or 
land diftrifts, pits have evidently been formed by art 
for the purpofe of catching fuch rain-water as may be 
brought to them by the ridge-furrows, ditches, or other 
fuch means, as well as that of land-fprings. The art too 
has been long praftifed on the fouthern chalk-hill parts of 
the kingdom, and ftill continues, in a great meafure, to pre- 
vail ; and on thofe, in fome northern diftrifts, it has been 
more lately eftabhftied, and fpreads itfelf on the neighbour- 
ing heights with vaft benefit. It is certainly neceffary and 
ufeful in all dry high fituations. It may probably, in fome 
cafes, alfo be collected into fuch pits, from the roofs of the 
buildings, for fuch purpofes,with much advantage ; though it 
has been much too common to draw it up, at great labour 
and expence, from deep wells formed in the bowels of the 

Lately much more attention has been beftowed on this 
matter than was formerly the cafe, in moft places, and in 
fome with the greateft fuccefs and benefit. It fhould never 
be neglefted where the want of it is confiderable, as live- 
ftock never do well under fuch circumftances. See Pond-^ 
Made Streams, and Watering Live-Stocl. 

Water, Sea, Management of Land gained from, in Agritul- 
ture, the bringing ground of this fort into cultivation. It 
has been obferved, that the principal difiiculty that can oc- 
cur in any fituation will be to keep off the water of the 
rivulets or rivers that may come from the furrounding lands, 
and to carry away and dehver to the fea the furface-water 
collefted from the land gained : the next important con 
fideration is that of clearing this land of furface incum- 
brances. It will often happen, it is faid, that the ground 


to be defended is interfered by a river. This is, it is 
thought, the moft expenfivc and difficult cafe that can occur ; 
but it is here only neceflary to carry the defence along each 
fide of it to the fea ; and there, wiicre it interfefts the other 
line of defence, to place a flood-gate, which may prevent 
the tide from entering, except when it may be neceflary to 
admit veflels or other things, and which (hall allow the water 
of the river to pafs into the (ca. Small rivulets and fprings 
may either be turned along the margin of the land gained, 
and be let out at one end of the defence where it joins the 
Jand, or be led the moil convenient way to one or more of 
the valves or flood-gates, which it is neceflary to make in all 
defences for excluding the water within. The water col- 
leAed on the furface of the land gained, may generally be 
let ofiF by the above flood-gates or valves ; but where the 
defence is extended into the water, this cannot be the cafe, 
as the level of the fea will moftly be above that of the land. 
In this cafe, wind-mills for driving pumps muft be placed at 
proper diftances, according as the particular cafe may be. 
Perhaps, in general, one fmall wind-mill driving four pumps, 
may be fufficient for freeing a thoufaiid acres of ground of 
water. The expence of fuch a pump-mill would not, it is 
faid, be above twenty or thirty pounds. By making a 
fmall defence-bank, fi-om two to four feet high, fome dif- 
tance within the larger one, all the water collefted between 
that and the original fhore would be accumulated ; and it 
might be led in a raifed canal in the fame level to a flood- 
gate in the outer defence. This would, it is thought, leave 
very Httle water to be drawn up by the pump ; and in this 
way, though twenty thoufand acres were gained, one wind- 
mill only would be neceflary. Often, and indeed in moil 
cafes, in place of a wind-mill, the brooks, rivulets, or fprings 
coUeAed within, might eafily, it is faid, be made to turn a 
.water-wheel, which would be more permanent and uniform 
than that turned by the wind. A bafon might alfo be con- 
ftrufted, fo that the ebb and flow of the tide would turn a 
draming-wheel ; and a great many other methods might, it 
is fuppofed, be fuccefsfuUy adopted. Thus, in land gained 
from the fea, there cannot, it is thought, be any difficulty 
in preferving it from water, from whatever quarter it may 
come. When the land to be gained is more or lefs covered 
with fl;ones, thefe fliould be put in flat-bottomed boats at 
low water ; and when the tide floats them, they fliould be 
rowed to the propofed line of bank defence, and be then 
dropped. This mode of conveyance will generally be found 
the moft economical for all the folid materials which are at 
a diftance. Where the ground is fandy or poor on the fur- 
face, and argillaceous earth or rich loam below, it may be 
trench-ploughed to fuch a depth, as to turn up the good 
and bury the bad foil. If the foil be fliallow, and even 
rocky, it may ftill, it is faid, be rendered valuable. The 
moft rocky parts may be covered five or fix inches 
deep with mouldy matters, and the whole be fown with 
cither meadow grafs-feeds, to be floated with frefli water, or 
kept as meadow ; or with other proper and fuitable grafs- 
feeds, and kept as falt-marfli. When mud of a good quality 
and confiderable depth is gained, it may, in fome cafes, it is 
thought, be defirable to fummer-fallow it for one or more 
feafons, after it has been fecured from the fea. At other 
times it may be belter to fow it with rape-feed for the fird 
feafon, and to fummer-fallow it the next, as a preparation 
for a corn-crop, &c. 

It is obferved that no fort of land can be gained from 
the fea but what is of great value for the purpofe of culti- 
vation, and efpecially as it can for the moft part be flooded 
by frefli water as well as by that of the fea at all times. By 
flooding, the moft barren fimd or rock, with only an inch or 

two of foil upon it, will bear excellent pafture. Indeed, 
much of the fand in thcfe fituations that is often reckoned 
barren and ufelefs, is mixed with broken fliclls, and on being 
examined will be found to contain three or four parts in ten 
of calcareous matter. Moft of the large rocks, too, within 
the fnlt-water mark are, it is faid, in a ftate of rapid decom- 
pofition, and fo fragile on the furface, as to be eafily pene- 
trate"d by the roots of grafs-plants ; more particularly after 
they have been expofed for fome length of time to the 
aftion cf the almofphere. The large detached ftones often 
found within the water-mark are not here meant, as thefe 
are fuppofed to be either buried in the ground, or boated 
off as above ; but thofe continued rocks which frequently 
conftitute the bafis of the fea-fliore for great diftances, 
the furface of which is fo completely oxydated, and occa- 
fionally decompofed and reduced fo as to be called rotten, 
that they are capable of aflbrding either an excellent ma- 
nure for certain foils, or are fit and proper for fupporting 
the vegetation of faline plants in their adlual condition. 

The quantity of land of this fort that is eafily capable of 
being obtained and thus cultivated is very confiderable 
indeed, perhaps not lefs than fome millions of acres in the 
whole idand. See Waste Laiui, and Watering Land. 
Alfu SALT-Mar/i. 

Water, Gum. See Mucilage. 
Water, Hungary. See Hungary Water. 
Water, Laurel. See Laurel. 

Water, Lime, is common water, in which quickhme 
has been flaked. See L.iME-lVater. 

Waters, Ophthalmic, or Eye, are fuch as are good in dif- 
orders of the eyes. See Collykium, Eve, and Ophthal- 

Water, Tar. See T \K.-lVater. 

Water, in Anatomy, &c. is applied to divers hquors, or 
humours, in the human body. 

Such is the aqua phlegmatica, phlegmatic water ; which is 
a ferous fluid contained in the pericardium. 

Water, in Geography and Hydrography, is a common, or 
general name, applied to all liquid tranfparent bodies, flow- 
ing on the earth. 

In this fenfc, water and earth are faid to conftitute our 
terraqueous globe. 

Some authors have raflily and injuriouny taxed the diftri- 
bution of water and earth in our globe as unartful, and not 
well proportioned ; fuppofing that the water takes up too 
much room. 

The quantity of water on this fide our globe. Dr. Cheyne 
fufpefts to be daily decreafing ; fome part thereof " being 
continually turned into animal, vegetable, metalline, or mi- 
neral fubftances ; wh'ch are not eafily difl^olved again into 
their component parts." Philofoph. Princip. of Relig. 
Many modern philofophers are of the fame opinion. 
An inundation, or overflowing of the waters, makes a 
Deluge; which fee. 

Water, among Jewellers, is properly the colour or luftre 
of diamonds and pearls ; thus called, by reafon thefe were 
anciently fuppofed to be formed, or concreted of water. 
The term is fometimcs alfo ufed, though lefs properly, for 
the colour or hue of other precious ftones. 

Water is alfo ufed in divers ceremonies, both civil and 
religious. S\\c\\ ^re xhe baptifmal water, holy -water, &c. 

Water, Holy, is a water prepared every Sunday in the 
Romifli church, with divers prayers, cxorcifms, &c. ufed 
by the people to crofs themfelvcs with at their entrance, 
and going out of church ; and pretended to have the virtue 
of waftiing away venial fin«, driving away devils, preferving 




from thunder, diffolving charms, fecuriiig from, or curing 
dife^fcs, &c. 

Tlie ufe of holy water appears to be of a pretty ancient 
Handing in the church : witnefs St. Jerom, in his life of 
St. Hilarion, and Gretfer, de Benedift. cap. x. 3cc. — M. 
Godeaii attributes its original to Alexander, a martyr under 
the emperor Adrian. 

Many of the reformed take the ufe of holy water to have 
been borrowed from the luftral water of the ancient Romans: 
thougii it might as well be taken from the fprinkling in ufe 
among the Jews. See Numbers, xix. 17. 

Urban Godfrey Siber, a German, has a difTertation, 
printed at Leipfic, to (hew, by proofs brought from church 
hiftory, that one may give holy water to drink to brutes. 

Bitter IVaters of Jealoufy. — In the Levitical law, we find 
mention made of a water, which ferved to prove whether or 
no a woman were an adultrefs. The formula was this : the 
pried, offering her the holy water, denounced, " If thou 
haft gone afide to another, inllead of thy hulband, and if 
thou be defiled, &c. the Lord make thee a curfe and an 
oath among thy people, by making thy thigh to rot, and 
thy belly to fwell ; and this water fhall go into thy bowels, 
to make thy belly to fwell, and thy thigh to rot." And 
the woman fhall lay. Amen. " Thefe curfes the prieft (hall 
write in a book, and blot them out with the bitter water. 
When he hath made her drink the bitter water, it (liallcome 
to pafs, that, if (he be defiled, the water (hall enter into 
her, and become bitter, and her belly (hall fwell," &c. If 
fhe be not defiled, (he fhall be free, and conceive feed." 
Numbers, chap. v. 

Water, Jnierdi&ion of Fire and. See Interdiction. 
Water of Flax and Hemp, &c. that which is ufed for 
deeping or raiting them in, in the view of procuring the 
pare vegetable fibrous matters that they contain. The wri- 
ter of the " Elements of Agricultural Chcmiilry" has ob- 
ferved, that this water polFefTes confiderable fertilizing 
powers. It appears, it is faid, to costain a fubftance ana- 
logous to albumen, as well as much vegetable extraftive 
matter. It putrefies very readily. And that as a certain 
degree of fermentation is abfolutely necelTary for obtaining 
the matters of the flax and hemp in a proper ftate ; the 
water to which they have been expofed (hould on that ac- 
count be ufed as a manure as foon as the vegetable fibre 
is removed from it. 

Water, Black, a difeafe in neat cattle and fheep, which 
is not unfrequently of a ferious nature. It has not, how- 
ever, been yet properly or fully inveftigated. 

In neat cattle it is faid to arife from fudden changes in 
the ftate of the weather from heat to great cold, the taking 
of cold on being turned into low wet paftures in the early 
fpring feafon, and the want of proper water in long dry 
times. Some fuppofe too that it may be caufed by fre(h 
paftures of particular forts, and that certain vegetables 
picked up by the cattle may produce it. It confids of a 
difcharge of a dark black bloody nature from the kidneys, 
and fometimes probably from other parts of the body. It 
is moft probably produced by inflammation terminating fud- 
denly in a ftate of great debility and relaxation of the parts, 
fo as to admit the dark grumous blood thrown out to pafs 
away in this manner. 

In flight cafes of this nature the cattle do not feem to be 
a great deal affefted by the difeafe, but wh»re the bloody 
fluid pafTed away is confiderable, and lalls for fome length of 
time, the animals become reduced to a very low ftate or con- 
dition, and great weaknefs is the confequence, which if not 
fpeedily removed by fome proper remedy, the cattle foon 
5ak under the preffure of the complaint. 

In the cure, except the difeafe be taken at its commence- 
ment, bleeding will feldom be ufeful or neceJTary, but the 
bowels fhould be well cleared out by powerful evacuating 
remedies of the fait kind, and kept properly open by their 
repetition, fo that the cattle do not become in the leaft con- 
ftipated, which would be hurtful and dangerous. When 
the difcharge continues, balls compofed of alum, ruft of 
iron, and armenian bole, made up with Venice turpentine, 
may often be of fervice, when given in fufficient quantities ; 
but a more powerful and effeftual remedy will be found in 
a ftrong dccoftion or infufion of bark, with vitriolic acid, 
and the tintture of opium, given in the proportion of a pint 
of the firft, two drachms of the fecond, and three drachms 
of the laft. This may be repeated once or twice in the 
courfe ot the day where neceffary, the bowels being always 
well kept open. 

By fome of thefe means the difeafe may moftly be re- 
moved without any great difficulty. 

Some think that much benefit often arifes from the ufe 
of nitre in full dofes in this diforder, as well as from the 
change of pallure, in fome inftances, as from low to fuch 
as are rather high in their fituation. 

Injheep the difeafe is charafterized by much the fame ap- 
pearances, taking place fuddenly, moft commonly among 
thofe of the hog kind, and fuch as are apparently ftrong, 
while feeding in rank paftures of the clover or other luxu- 
riant grafs kinds. In thefe cafes, there is fometimes much 
dark bloody watery fluid met with in the ftomachs of the 
flieep after death. The difeafe in thefe animals is moftly 
very rapid in its progrefs, therefore the fheep in fuch paf- 
tures fhould be conftantly well looked to, in order to dif- 
cover if any of them be indifpofed. 

In the prevention of the black water in thefe animals, 
fome have found great benefit by the ufe of about half a 
tea-fpoonful of fulphuric or vitriolic acid in mixture with a, 
fmall fpoonful of the compound tinfture of cinnamon, when 
given in a cup of cold water to each flieep in the morning, 
and cotting or houfing them in the night feafon. 

In other cafes, when the difeafe appeared to be prefent, 
much advantage has been faid to be produced by giving a 
ftrong infufion of pak-bark with aromatics, well acidulated 
with the fulphuric acid, and to which has been added a little 
of the tinfture of opium. The bowels are to be kept in an 
open ftate at the fame time. 

The immediate removal of the fheep into clofer fed and 
drier paftures, will always be attended with great benefit iu 
this difeafe, and the fupplying them with dry food might 
perhaps in fome cafes be of utility. 

Water, White, a name often given to a dangerous difeafe 
in fheep. 

Water in the Head, a denomination frequently applied 
to a difeafe in the head «f fheep. See GlD and Sturdy. 

Water Braxy, among yfnimalt, a difeafe in fheep, which 
has been difputed by fome ; but which the writer of the 
" Shepherd's Guide" is confident exifts, having feen and 
dilTeifted feveral cafes of it after death ; and is affured, too, 
that it does confiderable damage on fome particular farms, 
in fome fituations ; but that whether it be a fpecies of the 
common braxy or not, will, it is thought, admit of a doubt, 
though it is always viewed and confidered by the fhepherd 
as fuch. It is ilated in addition alfo, that in two external 
appearances it has a refemblance to it. The firft of which 
is, that the animal, when living, feems affedled much in 
the fame way, lying frequently down, and loitering be- 
hind the reft of the flock, appearing likewife fomewhat 
fwelled in the body. And that the next is, that, like all 
others affe&ed with the braxy of any kind, it will not bleed, 



to iny extent on opening a vein. The cutting of a vein in 
the tail, fpould, or below the eye, will make other (heep 
bleed plentifully ; but from thefe fcarcely a drop will iffue ; 
and even on cutting the principal vein in the throat, only a 
yery fmall quantity, it is faid, proceeds to flow out. 

However, in the interior appearances it differs very 
widely and materially. On opening the (heep, the whole 
entrails are, it is obferved, fwimming in bloody water, none 
of which is within the bowels, but only within the rim of 
the belly. The gall-bladder is very fmall, appearing as 
having been moftly fpilled previoufly to the death of the 
animal, and the urinal bladder is contrafted and (hrunk up 
to a fize fcarcely noticeable. The fmall fibres conneAing 
it with the other parts are inflamed, and on bringing it near 
the nofe fmells fomewhat like the other braxy. The bladder 
feems entirely without urine, but on blowing it up it is 
always quite found, and never burfts ; the guts and flefh 
are a little difcoloured, and have a fmell pecuUar to that 
diforder. The fmaller department of the ftomach or reid 
has fome purple fpots on it ; and, on being felt with the 
finger, thefe are thicker in the texture than the other parts 
of it. They feem, too, to have bled a portion inwardly ; 
this fome fuppofe iffues from the liver. 

In an effay inferted in the appendix to the Rev. Mr. 
Findlater's Account of the Agriculture of the County of 
Peebles in Scotland, it is faid to be a difeafe that is analo- 
gous to the fupprefGon of urine, which is caufed by the 
want of fu£Bcient aftivity and exertion. And that it con- 
fifts in the bladder being over-diftended with urine, whicli 
raifes violent inflammation in that organ, and produces an 
incapacity to difcharge the urine that is accumulated. The 
confequence of which is, that the urine regurgitates over 
the body ; the whole carcafe is tainted by fetid gafes ; the 
bladder becomes gangrenous, burfts, and the animal dies. 
That young and vigorous fheep are moft liable to this fort 
of braxy. And that the immediate caufe of the difeafe is 
feeding too freely on rich fucculent diuretic food, and rett- 
ing too long in the morning on the layers, taking place fre- 
quently when the fliephcrds are more negligent than ufual in 
removing them. 

It is fuppofed that the difeafe may be prevented by avoid- 
ing too free an ufe of fucculent diuretic food, and by 
moving the animals from the layers on which they are early 
in the morning, making them walk about for fome time in 
the view of encouraging them to pafs their urine and 

In attempting the cure, in cafe the bladder be greatly 
diftended and affefted, which may be known by there 
being a great fulnefs in the lower part. of the belly, the 
urine may be endeavoured to be drawn off by the introduc- 
tion of fuitable implements of the catheter kind, or by cau- 
tioufly letting it off by incifion of punfture, where that 
cannot be done. In either of thefe ways, when effefted, 
great relief will be afforded. 

And in the view of allaying or preventing inflammation, 
the ufe of proper purging and evacuating injeftions rtiould 
be had recourfe to, fuch as Glauber, or other falls of the 
fame kind ; or even warm milk and water be thrown up. 

The firft writer, however, thinks that no remedy for the 
difeafe has yet been pointed out that can be fully de- 
pended upon. See Braxy, and Striking ///, Blood, 
or Sicknefs. 

Water Farcy, a difeafe in liorfes of the (edematous or 
partial dropfical kind, which is often very troublefome in its 
removal. It has no relation or refenvblance, however, to 
that of the real farcy, being wholly different in its nature, 
caufes, and effc£i«, though fometimes ignorantly fuppofed 

to be of the fame kind. It occurs in horfet of all kind* 
and defcriptions, and at moft periods of their exiftence. It is 
a foft watery fwelling below the (kin, and is caufed by what- 
ever has a tendency to weaken and deftroy the natural vi- 
gour and ftrength of the body, whether in a local or general 
manner, but more efpccially in the former, fuch as low 
bad keep, want of fuflicient cleaning and drelTmg, taking 
the animals into cold water in a warm ftate, too great ex- 
pofure to cold rains, and many others. It often, too, 
happens after fevere colds of the epidemical kind. The 
fwellings take place in different parts, but particularly in 
the legs, having a pitted or dimpled appearance when preflTed 
by the finger. In fome cafes, the difeafe has a more 
general dropfical afpeft, the water not being confined to 
any one part, but (hews itfelf in feveral, over the whole 
body, by fuch fwellings. Thefe cafes, for the moft part, 
proceed from foul feeding, or tlie effefts of eating too 
greadily of rich luxuriant after-grafs. In the former cafe, 
the limbs and the whole body are fomelimes feen enormoufly 
fwelled, and become very hard, the belly and fheath parts 
being very greatly diftended. 

In the cure of the difeafe, in all the cafes, the great objefts 
are the removal and difcharge of the water, and the preven- 
tion of its future formation by every pofPible means. The 
former are to be attempted by the giving of ftrong diuretic 
purgative remedies, and the latter by the ufe of medicines 
of the ftrengthening kind, fo as to brace up and reftore the 
tone of the relaxed folids of the whole body. 

In the firft of the above intentions, the combining of 
calomel and fquills with jalap and aloes, in the proportions 
of about one drachm each of the two firft, to two drachms 
each of the two laft, for a large horfe, may be very ufeful, 
when made into a ball, and given every night, or every 
other night for four or five times, and repeated as there 
may be occafion ; throwing in, in the intervals, bark and 
other tonics, in full quantities, to reftore and keep up the 
ftrength of the animals. 

Rather ftrong infufions of the fox-glove with aromatics 
may hkewife be tried, and oak-bark in powder, with the 
fame, be given in large dofcs at the fame time they are 
made ufe of. 

The horfes (hould frequently, too, have good mafties in 
which nitre has been put. 

Gibfon, however, advifes the horfes to be purged once or 
twice in ten days, and to have intermediately a pint night 
and morning of the ftrong decoftion or infufion of black 
hellebore, prepared by boiling or infufing it in water, and 
then adding to four parts of it two of white wine, that has 
ftood upon the fame for fome length of time in a warm ftate ; 
or a ball compofed of nitre, fquills, and camphor, in the 
quantities of two drachms of the firft, three" drachms of the 
fecond, and one draciim of the third, made up with honey, 
and given once a day, either alone, or wafhed down with a 
hornful or two of the above infufion. 

The horfes (hould be kept warm, and have plenty of dry 
food while they are under thefe courfes of medicine. See 

WATKR^icif my}, a difeafe among fheep of the dropfical kind. 
It is a diforder, or fort of affetlion, arifing in the weak ftates 
of their conttitutions, which is incident to all the varieties 
of foil and climate, it is faid, in its different forms and de- 
grees of violence, from Shetland in the north of Scotland, 
to the moil fouthern parts of this country, wherever fheep- 
hu(bandry is carried on. It is obferved to occur, in general, 
among aged (heep, that are fubjeded to its attacks in confe- 
quence of weakiiefs, either of the more general or more 
local kind. It moft commonly feizes the animals towards 




thf end of the harveft-feafon and winter, and on farms which 
are moftly deftitute of flielter. It is, in faft, faid to be the 
genuine offspring of cold and moifture, and perhaps of every- 
thing that debilitates the vigour of the animals. 

The appearances that diftinguifh it to be prefent are 
fwellings in the legs towards night, which difappear in 
the morning, when the lower jaw often becomes a good 
deal fwelled. The eyes are dull, the urine, when noticed, 
is high coloured, the tongue is diy, and as the difeafe ad- 
Tances, the belly often becomes tenfe, and water is felt un- 
dulating in it, efpecially on being ilruck on one fide with 
one hand, while the other is kept iteady on the other fide. 
The (heep lofe their heart and vivacity, their appetites 
fail them, they become thin and lean, and at laft fall away 
and die. 

In regard to the prevention of the difeafe, a dry well- 
fheltered (heep-walk is faid to be good in that intention ; 
and the neighbourhoods of fea-fliores are ufeful in the fame 
view, as have been found by experience. But if the dif- 
temper fliould fhew itfelf in a fevere manner, in very wet 
feafons, in winter or fpring, night-flielter is found of parti- 
cular benefit in flopping the increafing flate of the malady. 
The animals, too, fhould have good, green, fwcet, diy 
hay chopped and given them, at the fame time with a little 
oats or bran in fome cafes. 

In the cure of thofe which are difeafed, a fhed or room 
in a houfe, and a full allowance of the fame forts of dry 
food, are particularly neceffary and ufeful. Some have tried 
tapping in the advanced flage of the diforder, but with 
only a temporary relief. Two drachms of cream of tartar 
given twice a day, in a little warm thin oatmeal-gruel, have 
been known to have a remarkably good effeft. In the 
more early ftages of the complaint, fmall quantities of 
calomel with fquills would probably remove the difeafe, 
efpecially if accompanied with a few hornfuls of a ftrong 
decoftion of oak-bark two or three times a week. By 
thefe means, difeafed fheep, when taken early, would per- 
haps be readily reftored. 

In the above-named part of Scotland, the difeafe is faid 
to be called by the title of fhell-ficknefs, as well as that 
which is here given it. 

W ATER-Calamint, in Botany, the name ufed by fome for 
a fpecies of mint. See Mentha. 

W ATER-Crowfoot, in Agriculture, the name of a plant of 
the weed kind, on which cows are faid by fome to be 
very fond of feeding. And in the fifth volume of the 
Tranfaftions of the Linnasan Society, Dr. Pulteney has 
obferved that it is not only relifhed by fwine, but that they 
thrive remarkably upon it, requiring little or other food 
until put up to fatten. The produce of it cannot, however, 
be great, fo that the ufe of it muft be limited. 

Watkr Cre/s, is Gardening, the common name of a fmall 
creeping plant of the herb kind growing in watery fituations, 
fuch as the fides of rivulets, rills, brooks, or other fmall 
trickling ftreams ; and which is much employed as a fallad 
herb, and for eating with bread and butter, or in other 
modes in its natural flate, as being highly cooling and 
agreeably bitter. See Cress. 

WATER-Dropworf. See Dnov-IVort. 

W ATER'Germander. See Germandeh. 

"Water- Hair-grafs. See Aika Aquatics. 

W ATER-Hemp-Agrimony. See Water-Hemp- A-CRMiOKy . 

VfATER-Leaf. See Leaf. 

WATER-Li/y. See NyiHTH^ffiA. 

Water Melon, the vulgar name of a plant of the melon 
kind, growing in aquatic fituations, and the fruit of which 
is of a watery infioid nature. See Cucurbita Ciirullus. 

Vol. XXXVlil. 

WATER-Par/nep. See Parsnep. 

WATER-Poa. See Poa Aquatica. 

WATER-Soldier, a (pecies o( Jlratiotes ; which fee. 

WATER-Tatk, in Sheep Hujbandry, a term applied to that 
fort of rank grafs that arifes from an excefs of wetnefs in 
fiieep-walks and paftures, and which has a tendency to pro- 
duce the rot in thefe animals. It may be caufed by too 
much wetnefs in the lands, either naturally, or by the ufe 
of water on them. It is this probably that makes water- 
meadows fo dangerous for (heep at certain periods. See 
Tath. and W ATER-Meadow. 

WAT^R-Ifen, ill Ornithology. See FuLICA Chloropui, 
Flavipes, and Rallus CaroUnus. 

WATER-Oasf/. See Sturni .': Cinalus. 

W ATER-Rail. See Rallis Aquaticus, and Benga- 

W ATER-Wagfail. See Wagtail. 

WATER-Dog, in Zoology, a variety of the Cams Fami- 
liaris. See Dog. 

W ATER-Elephani. See Hippopotamus. 

WATER-Z^og-. See Capybara. 

WATER-Rat. See Mus. 

W ATER-Aidle, in Agriculture, a term applied to the ftag- 
nant water contained in mofs land, in fome places, as in 
fome parts of the county of Lancafter. It is faid to be 
highly prejudicial to animals, when they drink water that is 
mixed or impregnated with it. It is beft removed from fuch 
land by proper draining, and frequent fuitable tillage culti- 

The bringing fuch wafles into a flate of improvement 
confequently difcharges it in an effeftual manner. See 
Moss and Waste Land. 

VJ ATER- Bailiff. See Bailiff. 

W ATER-Barroiv, Sluing, in Rural Economy, an improved 
contrivance of this fort. See Quendon Water-Barrow. 

WATER-Bearer, in AJlronomy. See Aquarius. 

W ATER-Bello'ws, in Mechanics, a machine ufed to blow 
air into a furnace, by the aftion of a column of water falling 
through a vertical tube. The orifice where the water enters 
the tube is fo contrived, that the water fhall be mixed with 
air when it enters the pipe ; and this air will be carried along 
with the flream through the tube, and is collefted into a 
proper receiver, from which it is conveyed to the furnace in 
a continued blaft. Thefe machines are much ufed on the 
continent, but have never been introduced in England, be- 
caufe they will not produce by any means fo great a current 
of air as may be raifed by the fame fall of water, when em- 
ployed to work bellows, or other machines, by means of a 

M. Reaumur has given a minute defcription of the water- 
bellows employed for the iron furnaces, in the provinces of 
Dauphine and Pays de Foix, in France, where fuch ma- 
chines are called trompes. The water is conduced to the 
furnace by a trough or paffage, having an inclination of one 
inch in a toife ; the body of the trompe is a vertical tube, 
about 27 French feet in height, and 16 inches diameter on 
the outfide : it is made of two pieces of fir hollowed out, 
and bound together by hoops of iron. 

The form of the interior of the tube contributes materially 
to its eSFeft. The mouth or upper orifice, where the con- 
duit-trough pours the water into it, is 13 inches diameter: 
from this it diminifhes, in the manner of a conical funnel, 
till, at a depth of three feet from the mouth, it is only four 
inches diameter, which part is called the throat. Here the 
opening of the tube enlarges all at once to a fize of nine 
inches, which it continues for all the refl of the height. 
Immediately beneath the throat, (that is, the upper part of 
T the 


the tube where it becomes nine inches diameter, ) ten vent 
holes are bored through the fides of the tube ; they are cy- 
lindrical, and two inches diameter ; their direftion is in- 
clined, fo that they point downwards at about an angle of 
45 degrees ; they are arranged at equal diftanccs round the 
tube in two rows, the upper row having fix holes, and the 
lower row four : it is through thefe holes that the air enters. 
The tube is fupportcd in a vertical pofition by a framing, 
and the lower end is introduced into a ftrong ton or ca(k, 
fix feet deep, and almofl as much in diameter, though it is 
rather fmaller at top than at bottom. The tube defcends 
through the head of the calk i8 inches, fo that it terminates 
within 4^ feet of the bottom of the cafk ; and a kind of 
table made of a flat round Hone, or a plate of caft-iron, is 
placed horizontally in the centre of the caflc, at i8 inches 
beneath the orifice of the tube, being fupported by a crofs 
of wood, placed upon four legs, from the bottom of the 
cafl<. The caflc is well clofed on all fides, particularly 
round the tube, where it pafTes through the head ; but there 
is an air-pipe conduAed away from the top of the caik, to 
convey the air to the furnace ; and from the bottom of the 
caflc there is an opening, by which the water can pafs away. 
The opening is regulated by a wooden (huttle, which pens 
up the water to fuch a height within the cade, that the 
opening through which the water ifl^ues will be always be- 
neath the furface of the water, fo as to prevent the efcape 
of the air by the fame paflage. 

The aftion of this machine is not fo eafy to explain as its 
ftrufture, and it has at various times occupied much of the 
attention of philofophers. Father Kircher was the tiill 
who defcribed the machine in his Mundus Subterraneus ; 
but he did not fatisfaftorily explain the reafon of its aftion. 
In the Memoires des Scavant etrangers, Barthes, the fatlier, 
has given a theory which is very defeftive ; and Dietrich 
was of opinion that the air was produced by the decompofi- 
tion of the water. 

M. Reaumur explains it thus : — The funnel of the tube 
is always full of water, which iffues rapidly through the 
throat ; but finding immediately a larger place, the ftream 
difperfes and fcatters into drops, becaufe it is no longer en- 
clofcd within a cylindrical furface : it does not, therefore, 
take any conftant figure, but the ftream is compofed of dif- 
ferent fmall ftreams, or rather fucceflions of drops, which 
are continually changing llicir pofition with refpcA to each 
other. Now the intervals between thefe feparate ftreams or 
drops are occupied by the air whicli is within the cavity of 
the tube : fuppofe tiiat between two ftreams feparaced by 
air a third comes to defceiid, it will pufli the air before it 
with all Its force, and carry the air down to the caflc ; and 
this will be replaced by frefh air, entering at the vent-holes. 
The irregular arrangement which the ftreams or drops take, 
either at their in"uing from the throat or in continuing their 
fall, is fuch that few drops do not carry fome air down be- 
fore them into tlie caflc : the water falling upon the table 
within the caflc daflics on all fides, and rcleafes the air which 
rifcs in the caflc, and ifl^ues through the air-pipe to the fur- 
nace, whilft the water falls to the bottom of the caflc, and 
efcapes gently through the fluice. 

A fingle trunk of the dimenfions juft defcribed is found 
fufficient to blow a forge or finery ; but for a fmelting fur- 
nace, three are joined together, having a common trough of 
fupply, and the air-pipes from the three caflcs are joined to- 
gether. M. Reaumur fuppoftd that a greater height of the 
fall would produce more air, becaufe it is longer expofed to 
thofe changes of pofition in the different ftreams of water ; 
but he fuppofed that no adequate advantage would be 
gained by an increafc of the diameter of the tube, becaufe 

it would be more likely, in falling in a large body, to A:, 
fcend in a clofer column. 

The machines of the Pays de Foix are fomewhat dif- 
ferently conftrufted : in thefe the water is conveyed into a 
refervoir, from the bottom of which a fquare trunk or tube 
defcends to the refervoir or air-cheft, which is made very 
long ; and the air-pipe proceeds from an elevated part of it, 
to prevent the danger of fpray or fmall drops being carried 
into the furnace. Inftead of a throat and the vent-holes, 
the tube is made to divide into two branches, at the point 
where it pafles through the bottom of the upper refervoir ; 
thefe branches rife above the furface of the water in the re- 
fervoir, fo that it cannot enter into them, but the water is 
admitted at an opening between thefe two branches, fo that 
in effeft the tube is divided into three, the centre being an 
opening for the water to defcend, whilft, the two outfide 
branches admit the air to mix with the water and go 

The editor of the Art des Forges fuppofes that the vent- 
holes are ufelefs, but that the violent agitation of the water 
in pafling the throat, and dafhing upon the table within the 
caflc, is fufficient to change the water into air. This is the 
fame hypothefis as that of Dietrich. 

Thefe various explanations rendered the fubjeft ftill more 
obfcure ; and in 1791, the Academy of Touloufe invited 
philofophers to determine the caufe and the nature of the 
ftream of air which is produced in thefe machines. M. 
Venturi, profeflbr of philofophy at Modena, gave the real 
anfwer in an excellent paper on the principle of lateral com- 
munication of motion in fluids. 

To explain the principle, this philofopher fuppofes a 
number of equal balls to roll along in a horizontal trough, 
in contaA with each other, with an uniform motion at the 
rate of four balls in a fecond : fuppofe, on arriving at the 
end of the trough, they fall fuddenly to a depth of 16 feet. 
Now, from the laws of gravity, each ball will perform this 
defcent in a fecond of time ; and as four balls fucceed each 
other in each fecond, it follows that there will always be 
four balls in the air at the fame time. The relative pofitions 
of thefe will be as follows : the uppermoft ball will be one 
foot from the point where they begin to fall, the fecond 
four feet, the third nine feet, and the fourth fixteen feet. 
This arifes from the acceleration which always takes place 
in defccnding bodies. A confideration of this circumftance 
will give a proper idea of the difunion and fucceflivc fepara- 
tion of the particles which the accelerating force of gravity 
produces in fluids, or in bodies which fall in a ftream. 

The rain-water flows out of gutters by a continual cur- 
rent ; but during its fall, it feparates into portions in the 
vertical direftion, and ftrikcs the pavement with diftinft 
blows. The water likewife divides, and is fcattered in the 
horizontal direftion. The ftream which iffues out of the 
gutter may be one inch in diameter, and ftrike the pavement 
over the fpace of one foot. The air which exifts between 
the vertical and horizontal feparations of the water which 
falls is impelled, and carried downwards. Other air fuc- 
cceds laterally ; and in this manner a current of air or wind 
is produced round the place ftruck by the water. M. Ven- 
turi went to the foot of the cafcadcs which fall from the 
Glaciere of La Roche Melon on the naked rock at La No- 
valefe, towards mount Cenis, and found the force of the 
wind to be fuch as could fcarcely be withftood. If the 
cafcade falls into a bafon of water, the air is carried to the 
bottom, whence it rifcs with violence, and difperfes the 
water all round in the form of a mi ft. 

He formed one of thefe artificial blowing engines of a 
fmall fize ; the vertical pipe was two inches in diameter, and 



four feet in height : it was a plain cylindrical tube, without 
any throat or funnel. But he found, when the water accu- 
rately filled the feftion of the orifice, and all the lateral 
openings of the pipe were clofcd, the pipe no longer emitted 
any wind. 

According to this writer, the circumftances which favour 
the moll abundant production of wind are as follows : — The 
reparation of the defcending balls is more rapid in the upper 
than in the lower part of the fall. In order, therefore, to 
obtain the greateft effeft from the acceleration of gravity, 
it is neceffary that the water ihould begin to fall at the orifice 
of the vertical tube with the leail poflible velocity, and that 
the depth of the water in the horizontal trough fliould be 
no more than is neceffary to fill the feftion of the vertical 
tube. The vertical velocity of this feftion is fuppofed to 
be produced by a height or head of water in the trough, of 
a depth equal to the diameter of the tube. 

We do not know by direft experiment the diitance to 
which the lateral communication of motion between water 
and air can extend itfelf, but we may with confidence affume 
that it can take place in a vertical tube, whofe feftion is 
double that of the original feftion with which the water flows 
from the trough into the pipe. Let us then fuppofe the 
feftion of the pipe to be double the feftion of the water in 
the trough, and in order that the ftream of water may ex- 
tend and divide itfelf through the whole double feftion of 
the pipe, fome bars, or a grate, are placed in the orifice of 
the vertical tube, to diftribute and fcatter the water through 
the whole internal part thereof. 

Since the air is required to move in the blowing-pipe with 
a certain velocity, it muft be compreffed in the receiver. 
This compreflion will be proportioned to the fum of the 
accelerations which (hall have been deftroyed in the inferior 
and clofe part of the vertical pipe, that is, the part beneath 
the vent-holes. Taking this clofed part of the pipe 1 5 foot, 
we fhall have a pretTure fufficient to give the rcquifite velo- 
city in the air-pipe. The fides of this portion of the pipe, 
as well as thofe of the receiver, muft be exaftly clofed in 
every part, to prevent the efcape of the air. 

The lateral openings in the upper part of the pipe may 
be fo difpofed and multiplied, particularly towards the top, 
that the air may have free accefs within the tube. 

In fome machines of this kind, the conftruftors feem to 
have been of opinion, that a great height was required in the 
water-fall ; but Dr. Lewis, who made a great number of 
experiments upon the fubjeft, (hews that an increafe in 
height can never make up for a deficiency hi the quantity of 
water ; four or five feet, he thinks, is a fufficient height for 
the water to fall : and where there is a greater height, it 
may be rendered ufeful by joining two or more machines 
together in fuch manner, that when the water has once com- 
mitted its air in the condenfing cad? or veffel, it (hall flow 
out into a new refervoir, and from thence defcend through an- 
other funnel and cylinder, and fall from it into a condenfing 
veflTel, where the air is extricated and carried off through 
the air-pipe. 

Another kind of water-bellows was invented by the in- 
genious Martin Triewald, of Sweden, and is defcribed in 
the Philofophical Tranfaftions. The machine confifts of two 
ca(ks or tuns open at bottom, and fo loaded, that they will 
fink into water in the fame manner as diving-bells. Thefe 
being fo fufpended that they can be alternately lowered 
down into water and drawn up again, will by proper valves 
and pipes afford a continual blaft of air. 

Fig. 15. Plate Water-works, reprefents thefe water-bellows 
in profile. A A are two ca(l<s, made nearly the fame (hape 
as diving-bells, being in the form of a truncated cone, or 

wider below than at top, where the/ are fumifhed with 
clofe heads B B, but at the lower ends A A are quite open. 
In the heads B B are valves V, which open inwardly, 
and are made like the palates of other bellows, with their 
hinges and the valves themfelves covered with hatters'- 
felt. They are caufed to (hut by eafy fteeJ fprings till the 
air from above opens them, which happens only when the 
bellows receive their motion upwards. The valves are (hut 
by means of the preffure of the air within, when they fink 
down into the water. 

On the fame heads two pliable leather tubes R R are 
fixed, one at the top at each water-bellows, which tubes are 
made and prepared in the fame manner as thofe ufed in 
water-engines for extinguiihing of fire. Thefe leathern 
tubes or pipes reach from the bellows to the tubes T T, 
which carry the wind into the furnace, or any other place, 
according to pleafure. 

Thefe two bellows are fufpended from the lever by iron 
chains K K, which are fattened to two fweeps S S, by which 
means they hang perpendicular from the balance-beam, and 
at the fame diftance from the centre of its motion C on the 
oppofite fides. On the top of this balance-beam are fixed 
two (loping gutters F F, into which the ftream of water runs 
from the gutter G, and gives motion to the whole work, 
performing the fame fervice as an overlhot or any other 
water-wheel ; but they coft much lefs, and give as even and 
regular motion as a pendulum, for as foon as fo much water 
runs into either of the inclined planes of the gutters F F, 
that the weight of the water exceeds the friflion near the 
centre of motion C, and the weight of that bellows which 
is funk down into the water, the gutter immediately de- 
fcends with an increafing velocity till the balance meets with 
the refiftance of the wooden fprings H H ; during this time 
it has raifed the oppofite water-bellows, or that bellows 
which is fixed under the oppofite gutter, the gutter 
which has been filled being come down to the fpring H, 
delivers all the water it has received, and at the fame time 
the water begins to run into the oppofite gutter, which re- 
ceives its load of water almoft as foon as the former is emp- 
tied, fo that one of the gutters begins its effeft as foon as 
the other has finiihed, and this continues alternately as long 
as the ftream of water is fupplied. Thefe doping gutters 
upon the balance-lever, therefore, perform all the effeft 
which a water-wheel does in working the ordinary bellows, 
and by means of the fame power of defcending water, but 
afting reciprocally on oppofite ends of the balance-beam. 

Thefe water-bellows blow the fire on the fame principle, 
which produce the effeft of the ordinary bellows, viz. that 
the air which enters the bellows, and which they contain 
when the top is raifed, is again compreffed or forced into a 
narrower fpace when the bellows clofe ; and fince air like 
all other fluids moves to that place where it meets with the 
leaft refiftance, it muft confequently go through the opening 
which is left for it, with a velocity proportioned to the force 
by which the air is compreffed, and muft blow ftronger or 
weaker in proportion to the velocity with which the top 
and bottom of the bellows are made to approach each other ; 
the blaft alfo will laft a time proportioned to the quantity 
of air that was drawn into the bellows through the -valve or 

The fame operation takes place in the water-bellows, for 
the air which they contain muft neceffarily be compreffed 
by the water, which rifes alternately into the bellows A A, 
and obliges the air to go through the leathern tubes R R, 
as being the place where the air meets with the leaft re- 

In this machine, the chief part of the weight to be 
T 2 moved. 

w A r 

^v A T 

movf d is balanced m equilibrio, for the bellows A A may 
be confidered as two nearly equal heavy weights in a pair 
of fcales, which in a great part balance each other. The 
difference is occafioned by that bellows which finks down 
into the water, being fo much lighter, as it lofes its weight 
by the quantity of water it difplaces, from the bulk of air 
contained beneath the furfacc of the water. This difference 
is compenfated by the weight of the water which falls 
down along the Hoping gutter, which acquiring the power 
of a falling body, increafes in the fame proportion as the 
bellows to be raifed by it increafes in weight ; for the 
bellows which fmks down into the water does not at once 
lofe its weight in the water, but gradually as it defcends 
deeper ; and in the fame manner, the afccnding bellows does 
not at once become heavier than the other, but the weight 
gradually increafes from the time it is iirft. raifed till it is 
quite raifed. 

Mr. Homblower fome years ago propofed an hydraulic 
bellows of the fame khid as M. Triewald's, except that, to 
avoid the flexible tubes of leather R R, he employed a lead 
pipe to go down to the bottom of the ciftcrii of water in 
which the bellows defcended, and turn up again beneath the 
bellows, fo that the orifice of the pipe was above the furface 
of the water ; it therefore communicated at all times froni the 
interior of the bellows to the furnace. Mr. H., in Nichol- 
fon's Journal, mentions a very ftriking difference between 
thefe water-bellows, in which the moving cheil was eighteen 
inches fquare and moved perpendicularly nine inches, and 
a common pair of fmith's leather-bellows of thirty inches 

The leather-bellows threw confiderably more air to 
the fire, and its nozzle, compared with the water-bellows, 
was as 73 to 60 in diameter, but it did not produce fo 
great an eff^ek in bringing on the heat ; and the noife of the 
water-bellows was fo great as to almoll drown tliat of the 
common one. The only difference in other refpefts is, that 
in the hydraulic bellows, the pipe went under ground for 
about eight feet, and the connecting pipe of the other 
came down about the fame diftance from the (hop above. 

WATER-Bomb, a name given by our chemiil Godfrey to 
a machine he invented on the plan of Greyl's difcovery, for 
the extinguifhing of accidental fires in houfes. He con- 
fidered firft, that the unchangeable fize of Greyl's engine 
was a very great objeftion, and on this plan contrived a 
medicated liquor, which was fuch an enemy to fire, that a 
very fmall quantity would exlingiiifh as much as a much 
larger of common water ; and this liquor had the farther 
advantage, that it might be kept ever fo long without cor- 
rupting, and by that means the veffels containing it would 
remain always fit for ufe ; whereas in Greyl's method they 
muft have been rotted by th.- corrupting and fermenting of 
the water, after a few years. The author of this invention 
tried it twice in public with us, and both times with all the 
fuccefs that could be wifhed ; but the llruAure of the veffel 
was fo much the fame with that of Greyl's, that Godfrey 
cannot be allowed any farther merit as an inventor, than 
that of contriving the medicated liquor inftead of common 
water. The macliine is a wooden velfel, made very firm 
and ftrong, that the liquor, when once put in, cannot leak 
out any where ; in the centre of this is an oblong cylindric 
veffel, which is filled with gunpowder ; a tube is brought 
from this to the head of the barrel ; and this being filled 
with combuftiblc matter, and the inner cafe with powder, 
and both made of plate-iron, that no water may get in, the 
veffel is then filled with the medicated, or antiphlogiftic 
liquor. The top of the tube is then covered, and the thing 
fet by for ufe. 

When there is occafion for it, it is only ncccffurv to un- 
cover the tube, and fetting fire to the matter in it, it is con- 
veyed to the veffel containing the powder, and the whole 
machine being thrown into the place where the fire is, is 
torn to pieces by the explofion, and the extinguidiing liquor 
fcattered every way about, on which the fire is quenched in 
an inllant. 

The contriver of thefe things propofed the making of 
tliree kinds of them, the one containing five gallons of the 
liquor : this was the largeft fize, and contrived for the 
largeft rooms, and moft urgent neceffilies. The fecond kind 
contained three gallons ; and the fmalled, which was meant 
for a clofet, or other little room, contained only two gallons. 
Thofe of the fmaller kind alfo had fometimes a pecuhar 
difference in their ftrufture, the powder-velicl- being placed 
not in the centre, but at the bottom : the intent of this was 
to fit them for chimneys, when on fire, as by this means the 
liquor, not being wanted to be fcattered on all fides, was 
carried moftly upwards. Thefe were fixed on the end of a 
long pole, and by this means thruft to a proper height up 
the chimney ; and the tube that communicated the fire waD 
placed downwards. 

The manner of ufing the machines for rooms on fire, is 
this : the perfon who has the care of them is to throw them 
as nearly as may be into the middle of the room, and then 
to retire to a Utile dillance : as foon as he hears the explo- 
fion, he may fafely enter the room, and with a cloth, or any 
thing of that kind, put out any remaining fparks of fire 
that there may be in particular places. If the room be fo 
large, that one of the machines cannot difperfe the hquor to 
every part of it, two are to be uled, one being laid at each 
end : and if feveral rooms are on fire at once, as many of 
the machines are to be ufed, one being thrown into each 
room. If a whole houfe is on fire, the lower rooms are 
firft to be taken care of, and after thefe the upper, as they 

Our Godfrey had fcarce better fuccefs than his predeceffor 
Greyl ; for while he was making his public experiments, 
one Povey, coUetling fome of the fragments of his broken 
veffels, found out the ingredient uled in the medicated 
liquor, and made and fold the things in the fame place 
where he had proved his right to them. It is probable that 
the medicated hquor was no other than common water, 
with a large quantity of fal ammoniac, that fait having this 
virtue of extinguiftiing fire in a very remarkable degree. 
But it is to be greatly wondered at, that while all the world 
were convinced by experiments of the ufe of the machine, 
the author made but little advantage of it, and it is now dif- 
ufcd. ACl. Erudit. Ann. 1724, p. 183. 

The fociety of arts and manufaftures, &c. made trials 
of balls prepared in Mr. Godfrey's method, by his grand- 
fon, in a proper edifice creAed for this purpofe ; and they 
found, that, after the fire had prevailed tor a confiderable 
time, and the flame forced its way through the chimney and 
windows, it difappeared, and was entirely extinguiflied 
by the explofion of two of thefe balls. See Fire, Exlin- 
Sui/hing of. 

\f ATY.R- Borne, in the Sea-Language, denotes the ftate of a 
fliip, with regard to the water furrounding her bottom, 
when there is barely a fufficient depth of it to float her off 
from the ground ; particularly when flie had for fome time 
relied thereon. 

WATER-Cambleti. See Camhlet. 

Water, Catarad of. Sec Cataract. 

VfA-vs.R-Clect. Sec Clepsvdra. 

WATER-Cc/cufv, in Piiinlittg, are fuch colours as arc only 



diluted and mixed up with gum-water : thus called, in con- 
tradilliiiftioii to oil-colours. See Washing. 

The ufe of water-colours, makes what we call LIMNING ; 
as tliat of oil-colours does painting, properly fo called. 

Painters in water-colours have been often afBifted with 
the difeafe called colica piftonum, occafioned by the poifon- 
ous quality of feveral of the pigments which they ufe ; and 
which, by putting the point of their pencils between their 
lips, whilft they are iludying their fubjeft, they infenfibly 
fwallow. Dr. Fothergill fays, that, when the vomitings are 
abated, copious difcharges by ftool are procured, and the 
funftions of the bowels in a degree reftored to their ufual 
ilate by the method purfued in the cure of the colica pi(fto- 
num ; nothing contributes fo effeftually to rellore the ufe 
of the limbs, when impaired by thefe caufes, as the liberal 
and conftant ufe of the tinftura guaiacina volatilis ; which 
may be given in fuch quantity, as to keep the body gently 
open ; mixed with a hitle common fugar or honey, and then 
diluted with any weaker mucilaginous liquor, as thin gruel, 
or barley-water, or marfhmallows-tea. Med. Obf. vol. v. 

P- 394- 

W AT ER-Ci/Ierns, for Rural Purpofes, fuch as are formed 
for different domeftic ufes. In high, dry, upland fituations, 
cifterns of this kind are of great utility and importance in 
many parts of the country. In the account of the agricul- 
ture of the North Riding of Yorkfliire, it is itated that in 
the high eailern parts of it, water-cifterns or refervoirs are 
made by the inhabitants within the ground, which are highly 
ufeful : thefe, it is faid, are fed by the rain-water which 
falls upon the roofs of the buildings, and is condufted from 
thence by fpouts. That in thefe cifterns a very ample fup- 
ply of foft water is always ready at hand ; and that by their 
being under ground, and kept clofe, the water is fweet and 
fuitable for every domeftic or other ufe. 

A water-ciftern of this fort is ftated to be formed in this 
manner. A cube of the required fize being dug in the 
ground, and the fides made even and perpendicular, the bot- 
tom is covered with fo much clay, as that, when well beaten, 
will be four inches thick ; a foundation of ftone is then laid 
round the fides ; upon the clay, a brick floor is laid in 
terras, the furface of which fhould not be lower than the 
top of the foundation ; the fides are then built a fingle brick 
thick, and the bricks laid in terras, a foot fpace being left 
betwixt the wall and the earth, which is gradually filled 
with clay in a foft ftate ; and this well beaten as it ftiffens ; 
the whole is arched over, leaving a hatchway for a man to 
go in and clear it out, and an opening or paflage into a 
drain, for the furplus. water to run or be taken off, when 
the ciftern is full. 

The water is raifed for ufe by means of a pump. In 
thefe cafes, as keeping all external air out of the ciftern 
contributes, it is faid, much to the fweetnefs of the water ; 
the pipe by which the ciftern is fed fhould be continued to 
within a few inches of the bottom, and the furplus water be 
conveyed off by a pipe rifing from near the bottom to the 
extreme height the water is defigned always to be at, when 
that takes place, and there communicate with the drain : by 
thefe precautions, it is faid, there will be no more of the fur- 
face of the water expofed to the external air, than what is 
xvithin thofe pipes and that of the pump. 

This method of forming water-cifterns may be found ufe- 
ful, cheap, and convenient, in many places, where fuch water 
is neceffary to be preferved pure and fweet. 

Cifterns of this fort have fometimes the title of water- 
cellars, and are of great convenience and ufe for farm-yards. 
See Water, River, Colkaing of, and Watering Live- 

W A T 

W ATER-Cmr/eSf in Agriculture, are fuch lai'ges ditches or 

paffages for taking off the water as are formed, aud remain 

conftantly for the purpofe in different places, and properly 

belong to the pubhc. 

They fhould be kept conftantly well opened and cleared 

out, not having too much fall given them, fo as to deftroy 

the evennefs of their bottoms. See Sewer. 
Water, Cut. See Cw-Wattr. 
Water, Dead, in Sea-Language. See DsAO-fValer and 


WATER-Engine, in Mechanics, denotes either an engine 

to raife water, or any engine that moves by the force of 


WATER-Falls, in Ornamental Gardening, are thofe falls of 

water which are formed and introduced in pleafure or other 
grounds for the purpofe of producing ornamental and pic- 
turefque effefts, or which naturally exift in fuch fituations. 
Tiiey are of different kinds and forms, being fometimes of 
the nature of cafcades, and at other times contrived for the 
intention of driving fome particular fort of interefting ma- 
chinery, fo as to afford an agreeable and tfriking pifture in 
the rural fcenery of the particular place where they are had 
recourfe to. They are ufually conftruCled, where they do 
not exift naturally, either by means of large rocky ftones 
thrown rudely together into a fort of ridge form of head, 
over which the water palfes, formed in the way of weirs, or 
built in mafonry in a careful and exaft manner, according as 
the different nature of the circumftances and fituations may 
require. See Water. 

Mr. London, in his ufeful work on " Country Refi- 
dences," has well defcribed and delineated feveral different 
modes of forming water-falls. They fhould, he thinks, be 
natural, ftrong, and lafting, from the general form of the 
whole of the materials, the fecurity and folidity of their 
foundations, and the quality of the work and materials ufed 
in building them. 

Water, Foul, in Sea-Language. See Foul. 
W ATER-Fowl. See Fowl. 

V/ATER-Furro-w, in ^Agriculture, a deep open furrovy 
drawn by the common or a large double mould-boarded 
plough made for the purpofe, in a proper direSion of the 
field in arable lands, or thofe in the ftate of tillage, for the 
ufe of conveying and taking oft' the fuperabundant hurtful 
water, and preventing the ilagnation of it from injuring the 
crops. This is efpecially neceffary and proper in the winter 
feafon, and often in others. It is therefore effential that, as 
foon as poffible after fowing moft forts of grain, but par- 
ticularly wheat, when there is any difpofition in the foil or 
land to the retention of moifture in too large a proportion, 
there fhould be as many water-furrows opened in this way 
as may be fufBcient for carrying off and completely reinov- 
ing the excefs of water, and thereby preferving the ground 
in a properly dry and found condition for the healthy 
growth of the crops. It is obferved by the writer of a late 
Calendar of Hufhandry, that the making of proper water- 
furrows is a circumftance of much importance in the culture 
of wheat, but that it is oftentimes ftrangely neglefted. It 
is a work, however, that fhould be well and effc&ually per- 
formed on all lands, except thofe that are perfectly dry 
all the winter through. The water-furrows fhould be 
formed by the plough, as foon as the field has been finifhed 
ploughing, fowing, and harrowing, and then a fpit of earth 
fhould be dug from out of the bottoms of them, and laid on 
one fide oppofite the rife of the land or ridge, and the loofe 
mould in the bottom parts be well fhovelled and cleaned out* 
fo as to make a perfeftly free paflage for drawing off the 
wetnefs ; the openings of all the common ridge-furrovus 



being likewrtfe well cleanfed at tlie fame time, fo that the 
ivatcr may have an eafy fall out of every one of them into 
the large water-furrows. The number of thcfe large fur- 
rows mull conllantly depend on the variations of the furface, 
and fome other circumftances of the lands : the only general 
rule is to make them fo many in number, as that no water 
may be fuffered to Hand on any part of the land in the wet- 
ted weather. In the bottoms or low parts of fields, or in 
other places of them where there is a double flope of the 
land, it is necetfary to form and cut double water-furrows at 
the diftance of about a yard or four feet from each other, in 
order to take the water from each dcfcent fingly. 

The fame writer, too, farther adviles, that in all lands fown 
with clover or other gratfes among the corn, thefe forts of 
furrows Ihould be dug a fpit deep, and the mould raifed in 
that way be carefully thrown out. Many farmers, it is 
faid, are not attentive enough to this point. They only 
fcour the furrows in fuch cafes. They (hould, however, it is 
thought, confider how long the grafs crops are on the 
ground, which may be two or three winters ; confequently 
it muft be very material to fuch crops to he dry all that 
length of time, which fcouring alone will not effeft, at lead 
not in a fufficiently perfeft manner. Particular attention 
fliould alfo be paid to the fpreading of the earth that is dug 
out of the furrows in thefe cafes, as if the men be not cau- 
tioned, they will lay it too thick and injure the crops ; it 
(hould be chopped and rendered fmall, and then fpread 
with great care, in order that the feeds may rife freely 
through it. 

In the cafe of arable land, thefe furrows Ihould be often 
examined during the winter feafon, to fee that they are 
pcrfeftly open and free ; the clods, lumps, and other fuch 
matters that may have fallen into them, being cleared out by 
means of the fpade. 

This is a praftice which is either much overlooked, or 
very imperfeftly executed, in a great many diftricts of the 
kingdom. The fides of the furrows in thefe cafes fhould 
always be made to Hand firm, and to have a good (lope each 
way, which prevents their faUing in and mouldering down 
fo much. The name of water-furrow drain is fometimes 
given to this fort of furrow. See VJ \TE.v.-Furroiuing. 

W ATER-Furroiv Fall Plough. See the next article. 

WATER-Furrowing, a term ufed to fignify the operation 
of opening water-furrows. It is a fort of work moftly 
executed by the affiftance of a large plough for the pur- 
pofe and the fpade, but fometimes by the plough alone. 
And in fome parts of the county of ElTex, particularly in 
the neighbourhood of Colchcller, they have a nielhod of 
doing it by means of a machine that is termed a fall-plough : 
in the hues where this fort of furrowing is to be performed 
acrofg the Hitches or ridges, this fort of tool is ufed there 
once in fix, feven, or eight years, for the purpofe of lower- 
ing, or, as they call it, /tilling the furface. Tiiey firll gather 
four or fix furrows by the plough ; then follows this imple- 
ment acrofs thefe furrows, in their loofe frefh ploughed 
ilate, taking up the parts of the mould, and dropping them 
on the crowns or (ides of the flitches or ridges, and when 
finiOied, the water-furrows are ploughed and fcoured in t!ie 
common manner : the invention is faid to have merit, as the 
water certainly takes a freer courfe than in the ufual 
method. In a dry feafon, a large extent of ground can be 
done in a (liort time, at little cxpence, in this way. 

Some think this work done in the neateft. and moll effec- 
tual maimer by means of a (hovel ; and that an old worn 
(hovel is the bell for the purpofe. See WATEn-/"i/rrow. 

WATEU-Gaff, the name of a fimple contrivance for mca- 
furing and afcertaining the depth or quantity of any water 

W A T 

in its application to any purpofe, or otherwifc. See 

WATER-Gang, a term applied to a channel or palTage cut 
through any fpot to drain and free a place of water by car- 
rying off a dream from it. 

VJ ATER-Gavel, in our OIJ Wrilrrs, a rent paid for fi(hii>g 
in, or other benefits received from, fome river. 

ViATER-Gililing. See Gilding. 

WATF,H-/.anmjn, a fmall glafs inllrument, which is a tube 
of about three-quarters of an inch in diameter, with a ball 
about i^ inch at one end, the other end being hermetically 
clofed ; the ball contains water, and the empty fpace is ren- 
dered nearly a vacuum by boiling the fluid previoufly to 
fealing it. In this inllrument the heat of the hand applied 
to the wetted tube, is fufHcient to produce bubbles of 
vapour, which enter the ball, but fpecdily coUapfe. The 
feries of thefe condenfations is as quick as 15 or 16 in a 
fecond. But in the deam-engine the condenfation is prodi- 
giou(ly more rapid. When a fmall double deam-engine, on 
the conftruftion of Boulton and Watt, having all the parts 
and gear of the large engines, but its cyhnder being only 25 
inches diameter, and the length of llroke 6| inches, was fet 
to work ; it gave 600 ftrokes fer minute, or about twice as 
many as the beats of a common watch. By an eafy calcu- 
lation it may be (hewn, that the deani condenfed was then 
much more than 300 cubic inches per fecond ; and if the 
condenfation, indead of being eflfefted in maffes of about 
a pint at a time, could have been performed by fuccefiiTe 
collapfes of each cubic inch in an open fpace, the pulfes 
would have produced the tone of the lowed E flat in the 
treble chff. But the number of cubic inches condenfed in 
a large deam-engine, e. g. a three-feet cylinder with an 
eight-feet ftroke, will be eight or nine times as much at 
the ufual rate of working. See Nicholfon's Journal, 
vol. iv. 8vo. 

WATER-Level, the level which is formed by the furface 
of dill water, managed in fome way or other in a conve- 
nient manner for its application in different cafes ; and 
which is perhaps the trued of any for moil ufes. The term 
is alfo applied to and lignifies the level ufed in watering 
land, and performing different other operations in the bufi- 
nefs of agriculture. See Level, SpiniT-LcT'c/, and Wa- 
tering Land. 

"W ATER-Levels are alfo lengths of canal in fome places, 
that are not conneAed by locks with other navigations ; 
but at the ends of which the goods are unloaded into team- 
waggons. See Canal. 

WATER-Linc and Reel, the ftrong large line and reel of 
the garden kind, which is ufed in forming fome part of the 
works in watering of land. 

Wateh-A/W, (fee Slltp-Building), are the lines of 
floatation fiippofcd to be defcribed by the furface of the 
water on tiie bottom of a fliip. Of thefe the moll par- 
ticular are thofe denominated the lig/il 'water-line and the 
load ivaler-Unc ; the former, namely, the light water-line, 
being that line which (hews the deprcffioii of the fliip's body 
in the water when light or unladen, or when fird launched, 
called the launching draught of ivaler ; and the latter, which 
exhibits the fame when laden with all her guns and ballad, 
or cargo. 

V^ ATV.R-Logged, in Sea Language, denotes the date of a 
(hip when, by receiving a great quantity of water into her 
hold, by leaking, Sfc. (he has become heavy and inadlivc 
upon the fca, fo as to yield without refidance to the effort 
of every wave ru(hing over her deck. In this dangerous 
fituation of a fliip, the crew have no refourcc, except to free 



licr by the pumps, or to abandon her by the boats ae foon 
as poffible. 

Water, To Make. See Make. 

W ATBR-Machine. See Machine. 

WATER-Mead or Meadow, in jigriculture, a term ap- 
phed to that fort of meadow or other inclofed low ground, 
which is capable of being improved and kept in a conllant 
ftate of fertility and produftivenefs, by means of water from 
fome adjoining river, brook, or ftream, being thrown and 
condufted over it in the winter or other proper feafon. This 
manner and beneficial praftice of forming meadows has pre- 
vailed locally for fuch a very great length of time in different 
parts of the country, efpecially in Wiltfhire, Gloucefter- 
ftire, and Devonfhire, that it is extraordinary that it has 
not been generally adopted and introduced into other dif- 
trifts, where it is equally capable of being had recourfe to 
without great difficulty, and where it may be equally ad- 
vantageous and proper. This negleft has been afcribed by 
£ late intelligent writer to a deficiency of information among 
farmers in general, in regard to the nature and management 
of the bulinefs, and particularly in what relates to the nature 
of levels, and the means of adjufting them in different cafes. 
Thefe circumflances, it is fuppofed, have confined it to 
the weftern diftrifts and parts of the kingdom. Other 
caufes may, however, have operated in this way, as the 
facilities afforded by the fituations of the lands in general, 
the numerous rivulets and llreams always ready at hand for 
the purpofe, and many others of the fame nature. 

It is necefiary that water-meadows (hould have fuch a 
form, either by nature or art, as